My computer constantly reboots without any warning. It happens all the time, when I am working in Word, when I play video games, when I scan for viruses or spyware. I just got an NVidia GeForce 3 TI200, which was when I stopped getting error messeges. I used to get "Frequency over range", now it just restarts.

Is the PC overheating? Check the event logs for the last events prior to the reboots.

Where are the Event logs? And, if the pc is overheating, how do you fix it?

The event logs can be found under Control Panel -> Administrative Tools -> Event Viewer. If you click on an error, it will most likely give you a somewhat cryptic indication of the error scource. This is handy for tracing down service and driver errors. Overheating is caused by innsufficient transfer of heat away from the processor. Your BIOS may have a section for hardware monitoring that tells you the system and CPU temperature. The CPU should never be above about 45 degrees C (case temp less than 35). If you think it is over-heating, start your search at the processor and work your way out out. The simplest thing to check is that all your fans are working. Something may have got bumped when the video was installed. Also, if your video card is pulling too much current, your power supply may be overloading. Prob. need at least 300W for that box. Also make sure all the card are well seated. A loose card might cause this problem.

I found the Eventlog and it says: "The computer has rebooted from a bugcheck. The bugcheck was: 0x00000050 (0xf73c7d1c, 0x00000001, 0xa01252f1, 0x00000000). Microsoft Windows 2000 [v15.2195]." Help!