My Machine Got Crazy

I need some help from you all.My computer has gone crazy it seems.I have purchased new machine at my place but the problem is that suddenly my machine got hanged initially it got started and my antivirus was getting updated and suddenly it crashed down it was just as if it got hanged all things came to stand still.I tried to restart the machine and a message appeared :-
Windows could not start because following file is missing or corrupt:

You can attempt to repair this file by restarting Windows Setup using the original Setup CD-ROM
Select ‘r’ at the first screen to start repair.

But no use friends I have tried this too.What to do now?
Do I have to Format my machine?
Please help!!! Any suggestions???

rtginc ;You may be able the method depends a lot on your operating system.
So that would be the first thing anyone helping you would need to know.