Unwanted software has a habit of creeping onto your computer. You download one small tool, and suddenly there is a trial version of something else, a browser toolbar you never asked for, and a programme that launches every time you start up. The good news is that removing it safely is well within your reach. You do not need to be a technical expert — just methodical. Here is how to clean things up properly, step by step.

Use the built-in uninstaller first

Every version of Windows and macOS includes a straightforward way to remove programmes. On Windows, open Settings, then go to Apps and choose Apps & features. You will see a list of everything installed. Click on any programme you no longer want and select Uninstall. If you are unsure what something is, look at the publisher name and the date installed — a programme you do not recognise from a recent download is a strong candidate.

On a Mac, open Finder and go to your Applications folder. Drag the unwanted app to the Trash. Some apps also leave behind a dedicated uninstaller inside their folder — run that first if it exists, as it will remove supporting files more thoroughly.

• Sort by date to spot recently added programmes you did not intend to keep.
• Check the size — large programmes you never use are wasting space.
• Be cautious with anything labelled as a driver or system component; if in doubt, leave it alone.

Remove stubborn or hidden programmes

Occasionally a programme will not appear in the standard list, or the uninstall button does nothing. This is common with bundled software that arrived alongside a free download. First, try running the programme's own uninstaller: look in its folder in Program Files or Applications for a file named uninstall or uninst000. If that fails, restart your computer in Safe Mode and try again — this prevents background processes from interfering.

For programmes that still refuse to leave, you can safely delete their main folder after uninstalling, but only if you are certain it belongs to that programme. Do not delete folders in Windows or System32. A quick web search for the folder name will confirm whether it is safe to remove. Remember to empty the Recycle Bin or Trash afterwards to reclaim the space.

Check your startup settings

Uninstalling is only half the job. Many programmes add themselves to your startup list, which is why your computer may still feel slow after removal. On Windows, press Ctrl + Shift + Esc to open Task Manager, then click the Startup tab. You will see a list of programmes that launch at boot. Right-click any you do not need and choose Disable. Disabling is safe — it does not uninstall the programme, it just stops it running automatically.

On a Mac, go to System Settings (or System Preferences on older versions), then General and Login Items. Remove anything you do not recognise or need at startup. Be conservative: leave antivirus and system utilities alone unless you know exactly what they do.

• Look for updaters — many programmes add background updaters you can disable.
• Watch for cloud storage clients if you do not use them daily; they can be launched manually instead.
• Recheck after a month — new programmes may have added themselves again.

Tidy up browser extensions and toolbars

Unwanted software often leaves its mark in your web browser. Toolbars, search hijackers, and pop-up generators install as extensions. Open your browser's menu (usually three dots or lines in the top right) and find the Extensions or Add-ons section. Remove anything you do not actively use. If your homepage or default search engine has changed without your permission, reset those settings in the browser's Settings page.

It is also worth clearing your browser's cache and cookies if you notice strange redirects. In most browsers, this is under Privacy and Security. Choose Clear browsing data, select Cached images and files and Cookies, and set the time range to All time. This will not remove your saved passwords or bookmarks if you leave those boxes unticked.

Clear out leftover folders and temporary files

After uninstalling, some programmes leave empty folders in Program Files, AppData (Windows) or Library (Mac). You can safely delete these if you are certain they belong to the removed programme. On Windows, also run Disk Cleanup (search for it in the Start menu) and select Clean up system files. Tick Temporary files, Recycle Bin, and Thumbnails, then click OK. On a Mac, use Storage Management in System Settings to review large files and empty the Trash.

Be careful not to delete shared folders that other programmes might use. If a folder name includes a programme you still have, leave it. When in doubt, move it to a temporary folder for a week — if nothing breaks, delete it permanently.

Keep your computer clean going forward

Prevention is easier than cure. When you download software, always get it from the developer's official website rather than a third-party download portal. During installation, choose the Custom or Advanced option instead of Express — this lets you untick bundled extras. Read each screen carefully; the checkboxes for additional software are often pre-ticked.

Set a reminder to review your installed programmes every three months. A quick scan of the uninstall list and startup items takes ten minutes and keeps your machine running smoothly. If you share your computer, ask other users before removing anything — what looks like clutter to you might be essential to them.

Finally, keep your operating system and security software up to date. Updates often close the loopholes that unwanted programmes use to install themselves. With a little regular attention, your computer will stay fast, tidy, and free of software you never asked for.