Windows 7 Reinstall Help Can't Even Boot Computer

Hello all. I have a dell xps 8100 computer. I recently yesterday got a message that i found out is a virus. Its the one with the FBI page where it ask you to pay 200 dollars to unlock your computer. Well that page kept being there so then i system restore it and well that page isn't there anymore.

However... right now i cannot access my computer in regular mode. Only thing is safe mode. The other thing is i wanted to clean and reinstall my computer for a while but never did it.

However... I want to wipe out everything on hard drive. I see that page where it shows it here on the forum.... however... i cannot even access that page. I keep getting the message

clean is not allowed on the disk containing the current boot while on safe mode. Then right now... after closing and opening my computer multiple times... i get an error message and my comptuer can't even boot at all. Even when i put in my windows 7 cd in to reinstall and just forget about wiping it out... I cannot do this.

Can someone please help me?

Do you have your computer set to boot to DVD/CD drive in your BIOS?

I have no idea. How can i tell you the answer?

Work through these steps for Troubleshooting Windows 7 Failure to Boot.

How to Boot your Computer from a Bootable CD or DVD

Depending on your computer make and model, to get to the BIOS you usually have to press a function key. Common keys are F1,F2,F9,F10,F11,F12, and Delete. Then when you are in your BIOS, set your boot priority to the CD/DVD Drive.