Run Scandisk Utility. This will check for and repairs problems with the hard drive.
Run Disk Defragmenter.
This reorganizes your hard drive so that your applications and data load and run faster. If you have an SSD hard drive, this isn't a necessary step.
Delete all junk and spam email
messages.
Empty the "Deleted Items" folder in your email program.
Delete the Temporary Internet Files and Clear
History in your Internet browser.
Check for Critical Windows Updates.
Install anti-virus and anti-malware software and keep them updated weekly.
Install a pop-up blocker to minimize chances of infecting your computer with malware.
Make sure anti-virus
software is updated and that it scans your computer daily.
Uninstall any programs you do not use, or that have mysteriously
appeared on your computer.
Use compressed air to clean dust/dirt
out of the inside of your PC every few months. Pay particular
attention to the cooling fans as they tend to collect the
most dust. Be sure to physically disconnect the AC power cord
from your computer prior to opening your computer enclosure.
Have the computer and equipment plugged into a quality surge protector.