Problem xp registery corrupt

when booting my computer I get the following error: Windows can’t boot because the folowing file is missing or corrupted: \WINDOWS\system32\config\system I have a dell dimension 5150/510E computer with pre-installed windows xp media center edition. the cd and key aren’t provided with the computer. does anyone have a solution for my problem?
Answer #1
I suggest you get it reinstalled or completely refactoried
Answer #2
If i was you i would format and re install windows