There could be a lot of different causes but you’re going to have to get it to stop long enough to figure out the cause. What is happening is that your server is set to automatically reboot after a BSOD (blue screen of death) so what you need to dois disable that function so the blue screen information remains on the screen.
If it will give you enough time to do it, you can disable the automatic reboot from Control Panel, System, Startup/Shutdown tab, and uncheck the box marked “automatically reboot”.
If not, you’re probably going to have to do a parallel installation (assuming there is data to be saved) or re-install NT from scratch (if retaining the existing data is not a problem).
One other option, if your system partition has a FAT format, you can boot into DOS and then recover the memory dump file (usually called memory.dmp) and by using the dump file utilities (dumpexam.exe, chkdump.exe), you can usually deduce the cause of the failure.
Where I’ve seen this sort offailure most commonly is right after a hardware change (often the installation of a mis-matched memory module) so you might think back on anything that might have changed to cause this problem.