When I try to boot my system up

I get a black screen with this message

 

ERROR LOADING OPERATING SYSTEM

 

I have performed a 2000 recovery.  When I get to the prompt and chkdsk all volume is good. 

 

However When I try to boot my system from the hard drive I continue to get this message.

 

ERROR LAODING OPERATING SYSTEM

 

Is there a way to re-install the operating system without losing all my data on the hard drive?

 

Thank You.