Your computer is running slow, and there are several things you can check right now before calling IT. Most slow computers are not dying – they just need a bit of attention. This guide walks through the seven most common causes, in order of how easy they are to fix, so you can get back to work faster.

Check 1: Too Many Startup Programs Running

Time to fix: 5 minutes

When your computer starts up, many programs launch automatically in the background. Things like Spotify, Teams, OneDrive, Zoom, and software you installed once and forgot about all fire up at once. Each one uses memory and processing power, even when you are not actively using it.

How to identify it: Right-click the taskbar and choose Task Manager. Click the Startup tab. You will see a list of programs that launch at startup, along with their impact rating (Low, Medium, or High).

How to fix it: Right-click any program you do not need at startup and select Disable. You are not uninstalling it – just stopping it from launching automatically. Good candidates to disable include Spotify, Skype, Zoom (you can still open these manually), and any software with a “High” impact rating that you rarely use.

Check 2: Low Disk Space

Time to fix: 10–20 minutes

Windows needs free space on your hard drive to work properly. When your drive gets below about 10% free space, performance drops noticeably. Your computer basically runs out of room to think.

How to identify it: Open File Explorer and click This PC. You will see your drives listed with a usage bar. If the bar under your C: drive is red or nearly full, this is likely contributing to your slowdown.

How to fix it: Open Settings > System > Storage and run Storage Sense to clear temporary files, old downloads, and the recycle bin. You can also search for large files you no longer need. If you are storing a lot of video files or old project folders, consider moving them to an external drive or your organisation’s cloud storage.

Check 3: Malware or a Virus Running in the Background

Time to fix: 30–60 minutes

Malicious software often runs silently in the background, consuming your processing power and slowing everything down. A slow computer that was previously fast is worth scanning, especially if you have clicked any suspicious links recently.

How to identify it: Open Windows Security (search for it in the start menu) and check that protection is active and up to date. If you notice unusual network activity, unexpected pop-ups, or programs you do not recognise, treat those as warning signs.

How to fix it: Run a full scan from Windows Security (formerly Windows Defender). It is built into Windows and is genuinely effective. If the scan finds something, follow the prompts to remove it. For a second opinion, Malwarebytes offers a free version that is worth running alongside your existing antivirus. If you suspect a serious infection, contact your IT team rather than trying to resolve it yourself.

Check 4: Outdated Windows or Drivers

Time to fix: 20–45 minutes (mostly waiting)

Outdated software can cause slowdowns, security vulnerabilities, and compatibility problems. Windows updates often include performance fixes, not just security patches.

How to identify it: Go to Settings > Windows Update and check whether updates are pending. For drivers, open Device Manager (search in the start menu) and look for any yellow warning icons next to device names.

How to fix it: Install all pending Windows updates and restart your computer. For drivers, particularly your graphics card driver, check the manufacturer’s website or use Windows Update to install the latest version. This is especially relevant if your computer slowed down after a recent Windows update – a driver update often resolves it.

Check 5: Too Many Browser Tabs and Extensions

Time to fix: 5 minutes

Your browser is often the biggest memory consumer on a work computer. Each open tab uses RAM, and browser extensions pile on top of that. If you habitually have 20 or more tabs open, your browser alone could be consuming several gigabytes of memory.

How to identify it: Open Task Manager > Processes and look at how much memory your browser is using. If it is above 1–2 GB, tabs and extensions are likely the culprit.

How to fix it: Close tabs you are not actively using. Use bookmarks or a tool like OneTab to save groups of tabs without keeping them open. Review your extensions by going to your browser’s settings menu and selecting Extensions – disable or remove anything you do not actively use. Ad blockers are generally worth keeping; toolbars and obscure productivity extensions often are not.

Check 6: RAM Is Maxed Out

Time to fix: 5 minutes to diagnose, longer to resolve

RAM (Random Access Memory) is your computer’s short-term working memory. When you run out of it, Windows starts using your hard drive as temporary RAM instead, which is dramatically slower. Everything slows to a crawl as a result.

How to identify it: Open Task Manager and click the Performance tab, then select Memory. If your RAM usage sits above 80–90% during normal work, you are running low. Most business computers come with 8 GB of RAM, which is fine for basic tasks but can struggle with multiple applications open at once.

How to fix it: In the short term, close applications you are not using and restart your computer to clear memory. Longer term, upgrading from 8 GB to 16 GB of RAM is one of the most cost-effective ways to speed up an older machine. Talk to your IT team about whether your computer supports a RAM upgrade.

Check 7: The Hardware Is Genuinely Old

Time to fix: This one requires a conversation

Sometimes a computer is slow simply because it is old. A laptop from 2015 running Windows 11 with modern browser-based applications is working very hard. There is a limit to how much you can optimise aging hardware, and it is worth being honest about that.

Signs it is time for a new machine:

• The computer is more than 5–6 years old
• You have already worked through these checks without significant improvement
• It takes more than three minutes to start up after a restart
• It struggles with basic tasks like opening email or editing a document

The cost of replacing a computer is often less than the cumulative cost of lost productivity. Talk to your IT support team about a hardware refresh and what a modern machine would look like for your role.

How Copilot and AI Can Help

Windows Copilot and AI assistants are becoming genuinely useful tools for diagnosing performance issues, even for non-technical users.

You can ask Copilot directly: “Why is my computer running slowly?” and it will often guide you through relevant settings and checks based on your current system. It can help you interpret what Task Manager is showing you, suggest which startup programs are safe to disable, and help you decide whether a slowdown is likely a software issue or a sign that new hardware is worth considering.

AI is not a substitute for a proper IT support conversation, but it is a useful first step and a good way to gather more context before you call for help.

When to Call IT Support

Some slowdowns are beyond self-service. Contact your IT support team if:

• You suspect malware or a security incident
• The computer is freezing, crashing, or showing error screens
• Performance has dropped suddenly without an obvious cause
• You have worked through this list and nothing has improved
• The computer is business-critical and downtime is costing you money

The Otto IT team can remotely diagnose most performance issues quickly and get you back up and running without waiting for an on-site visit. Book a time with us here or contact us to find out how we support businesses like yours.

Frequently Asked Questions

Why did my computer suddenly get slow?

Sudden slowdowns are usually caused by a Windows update, a newly installed program, malware, or a hard drive that has filled up. Start with Task Manager and work through the checklist above to narrow it down.

Does restarting the computer actually help?

Yes, it genuinely does. Restarting clears RAM, applies pending updates, and closes any stuck processes. If you leave your computer in sleep mode rather than shutting it down properly, restarting once a week is a good habit to get into.

How much does it cost to speed up an old computer?

Adding RAM typically costs between $50 and $150 and can make a meaningful difference on machines that are 3–5 years old. Replacing a traditional hard drive with an SSD is another high-impact upgrade. Your IT team can advise whether the investment makes sense given the age of your machine.

Is 8 GB of RAM enough for a business laptop?

It depends on what you do. For basic tasks like email, documents, and web browsing, 8 GB is manageable. If you use video conferencing, run multiple applications at once, or work with large spreadsheets, 16 GB will give you noticeably smoother performance.

When should a business computer be replaced?

Most IT teams recommend a 4–5 year refresh cycle for business computers. Beyond that point, the combined cost of support, slow performance, and security risk generally outweighs the cost of buying a new machine.