Verified answer

http://crystalmark.info/software/CrystalDiskInfo/i...

download that program and run it, look at the harddrive status if it says caution then start backing up your data and prepare for a hdd crash if it says status is good then backup and reformat

You have a virus (this is common symptoms of a virus). Create a boot disc that contains one or more Anti-Virus, Spyware and Malware software in it, or download one that's already made and boot it up before you log into Windows. Viruses are easier to remove when they are not written onto your computer's memory.

After the virus is removed, defrag your hard drive. This will help speed up your PC.

To create your very own boot disc with your own software, here's a great place to start: http://www.howtogeek.com/howto/windows/geek-repair...