I don't think it can be undone. Once it's been restored it's real hard to do anything about it. However as I work for a Computer repair company, I would suggest that you call a few and see if anyone can help you. I've brought back 7 a couple of times, but have not had this issue with 8. Call around and see if someone nearby you can help ! Good luck !
Open System Restore by clicking Start button, All Programs, Accessories, System Tools, and then clicking on System Restore. Enter your administrator password when prompted, click Undo System Restore, and then click on Next. If this doesn't work, you'll have to talk to Microsoft support or a computer technician for professional assistance.