BOOT\FCD error, STOP : 0x0000007B error, a problem has been detected and Windows has been shut down

When I boot , then this error comes:

\BOOT\FCD

After that , I boot through a Windows XP installation CD , then it says this:

A problem has been detected and Windows has been shut down to prevent damage to your computer

STOP: 0x0000007B

Run CHKDSK /F to check for hard drive corruption and then restart your computer

Now, how to run this command when am not able to boot into Windows itself, so i how would i enter DOS by going to Start Menu -->Programs-->Accessories-->Command Prompt?

My important data was in the E:\ which was not having any Windows. I don't want to lose it.

You need to boot into the Windows XP install disk and select the checkdisk option from there.