Title says it all. Can I get rid of everything on my computer and start over?

Yes you can. It is called formatting. If you put your windows cd in and shut the 'puter down. Then when it starts up it will ask you if you want to boot from the cd. You may have to press F8 on startup and tell it to boot the CD. Then follow the instructions on the formatting route. If you have problems go online and get the actual steps print them out and then go for it. I have done it a few times but have had to get a little help from my bro. who works for microsoft. good luck.

You sure can, it's called formating. If you have the software that came with your computer there should be a restoration disk or disks. Pop that bad boy in and start up from disk. Follow the instructions on the screen.
If there's anything you want off your computer save it before you format.

Yeah, before you go hog wild, don't forget to make a backup of anything of importance to you.

Why star all over? If something has happened recently you can do a system restore to an earlier date. Maybe that will solve your problem and save all your data.