My PC self-reboots: Faulty Network Card or Cable
First thing you need to check is your network cable. There are cases where twisted or kink-laden cables (caused by office wear and tear) cause PCs to self-reboot. The simple solution is to replace the cable. I’m sure the supplies personnel in your office would not begrudge you of such a simple request. Or if you’re the one shouldering the cost, I assure you that your wallet won’t feel the loss.
If it isn’t the cable, then it must be the network card. Experts from Answers that Work suggest the 3com network card for servers. Just ask form your technician regarding this.