how can I restart my computer.. like RESTART IT?

Thats called recovery. You don't recover a computer without losing your data. Otherwise it wouldn't be a recovery. You will have to burn the data you want to save onto a disk or put it on a storage drive. Then use either the system recovery disc or OS disc to reinstall windows. You could try restoring it back as far as you can but, if you have a virus, don't bother cuz that won't get rid of it.

If you want it to run like a brand new computer you would have to reformat your hard drive, which would delete all of your stuff. You could reinstall Windows w/out a reformat. It wont run quite as well as brand new but it should run better.

Put your windows disk and have it boot off of it (check your mother boards website for how to do this)> install windows> install over previous install (im not sure how it is worded but its something like that) > let the install go (Make sure you have your CD key, no CD Key, no Windows/computer).

I am probably missing some steps but that is the rough outline.

Backup your documents and files to DVD-R.

Format Harddrive

Install Windows.

Ah, you will have to download a program to completely clear out the drive.

Start/control panel/system restore to the earliest date in its calender.

impossible. If you dont care that much you can always reset your computer to what they call default settings or factory setting. you would have to check your manual or contact your pc manufacturer

go to bios