Malware, spyware, and adware can slow down your computer tremendously. Though there are many free utilities out there that can scan your computer and remove these nasty critters, I personally recommend Microsoft Security Essentials
because it is a free antivirus, malware scanner, keylogger scanner, and much more.
Download it here: http://windows.microsoft.com/en-us/windows/security-essentials-download
Now install it, and run the Quick
or Full Scan
(recommended). Quarantine or remove any issues it finds. For advanced users
: I also recommend installing Malwarebytes Anti-Malware
. It helps you take fighting malware to the next level.
You can download it here: http://www.malwarebytes.org/products/malwarebytes_free/