Lag is often fixed, or at least partially alleviated, by performing maintenance on your computer. Shutting down programs you aren't using and modifying when they start helps free up memory, but you can also make sure there are no software conflicts by uninstalling unneeded security programs. Error-checking and maintenance help to clear space on your hard drive and correct errors that may cause your computer to lag or freeze.
Shut down any programs that you're not currently using. Even if your computer has plenty of memory, running many programs at once will end up making things run slowly and can cause lag. Close the programs individually or use Task Manager to see what's currently running and end the processes from there.
Adjust your operating system's performance options to optimize performance, rather than appearance. This will take away many visual effects and animations that can slow your computer down. From your charms screen, type "effects," then press "Enter." From the results that appear, click "Adjust the appearance and performance of Windows." Click "Adjust for best performance," then click "OK" to save your changes.
Check your list of installed programs to make sure you only have one anti-virus and anti-spyware program installed. If you have more than one anti-virus program, they can conflict with each other, causing performance issues and errors. You only need one program each for viruses and spyware, so uninstall any extras.
Perform a disk error check to check for issues that may be causing your computer to lag or freeze. This function, called chkdsk, scans for errors and data corruption that can be caused by improper shutdowns, corrupted software or corrupted metadata. Open "My Computer," right-click on your main hard drive, then click "Properties." Click the "Tools" tab, then click "Check." If you are told that you don't need to scan your drive, click "Scan drive" to perform the scan anyway. If any errors are found, your computer will attempt to repair them automatically.
Use the "System Maintenance" tool to check for errors and clean up unused data. Open the Control Panel, then type "troubleshoot" into the search box. Click "Troubleshooting," then under System and Security, click "Run maintenance tasks." This process will run on its own and should not take long to complete.
Refresh your computer using your PC Settings. Refreshing your computer keeps your files and personalization settings, but wipes any programs that were installed from outside the Windows Store and resets the rest of your computer's settings to default. This is a slightly more drastic option, but resetting your computer to almost new will help increase its performance. If little else is working and you don't mind reinstalling some programs, this option may help. Even though this backs up your data, back it up on an external hard drive of your own first, just in case.
While you're checking your list of running programs in Task Manager, you can also change which programs run automatically when you start your computer. Open Task Manager, then click the "Startup" tab. Click any program, then click "Disable" at the bottom. This won't uninstall the program, but it will make it wait until you click its icon to start. This will prevent unneeded applications from running when you turn your computer on and will help speed it up.
After you've made sure that you have only one anti-virus and anti-spyware program on your computer, run a full scan of your computer with both. Viruses and spyware can slow your computer down quite a bit.
Avoid ending any processes if you don't know what they are, as they could be integral to your computer's normal operation. If you do accidentally end a process that causes your computer to malfunction, simply restart your computer; the process will restart as usual when your computer starts again.
- CmdrKeene's Blog: Visual Effects and Performance Options in Windows 8
- Microsoft: Troubleshoot a Problem With Your Antivirus Software
- The Windows Club: Disk Error Checking in Windows 8
- Microsoft: Open the System Maintenance Troubleshooter
- Paul Thurrott's Supersite for Windows: Windows 8 Tip: Reset or Refresh Your PC