Boot from a Ubuntu disc and recover data
First I'd go to http://www.ubuntu.com/download/desktop and download Ubuntu to make a bootable disc. Then I'd use that to recover any data I want to keep. Then I'd restore to factory settings. If you don't have the discs to do that, see if your manufacturer will ship them to you for a small fee.
When you've gotten your system back like you want it, I urge you to get yourself an external hard drive and a good 3rd party backup program. You can set it up to do everything automagically at the time and frequency of your choice. 1 TB external hard drives are about $70 these days and a really good FREE backup program is the Easeus todo backup free which you can download from
http://www.todo-backup.com/products/home/free-backup-software.htm . That can save you a lot of time and frustration the next time something like this happens. Sooner or later it happens to all computers for one reason or another.