Your can  go to system and reset to earlier date.

You should have internet security, which helps to block sites that causes problem. Sometimes you can get free after mail in rebate, you may get 10 dollars discount if you sign through gmail in buy.com.

How do you save your files, Best way is keep them in removable disk, now a days if you pay about 30 bucks,  you may  get 40-60 gb hard drive.

Last option is to re-download the operating system. Thats all I can suggest.