I have a compaq presario laptop and it was working fine. The next minute I got the error message on a black screen saying:

<Windows root>\system32\ntoskrnl.exe
Please re-install a copy of the above file.

I tried to boot up using Windows XP cd but it did not work. The safe mode does not work either. I loaded the repair console but it also couldn't finish the job. I talked with an HP tech support rep but he recommended to format the hard disk. But I have valuable data on it!

If anyone know of a way to re-install the file above or fix this problem, please let me know. I will appreciate it.