Autocad fatal error occurred on Windows XP OS SP3

Hi experts,
I am running Windows XP OS SP3 and have run MEP09. I got the following to error message saying “This version of AutoCAD was not installed properly”. I reinstalled the software but the same error message displayed followed by the “Fatal Error” and the program immediately crashed. Is there any way to resolve the issue? Help me.
Thanks.
I can no longer operate MEP09 at all!

Error: This version of AutoCAD was not installed properly and some features may not run correctly. You should reinstall AutoCAD immediately to make sure all features are working properly. Do you wish to continue anyway? FATAL ERROR: Unhandled Access Violation Reading 0x0000 Exception at 749e5eh
