Have you moved the computer recently? I had exactly the same problem. I moved and set up my network in my new apartment. At the time I was running 95 on my work machine, a Netware 5 file and print server and Linux on another machine. All are home built machines but the 95 was a rebuilt OEM machine which I bought in 1991. It started rebooting spontaneously but never under any certain set of circumstances I could identify. Over the next years I replaced the power supple, upgraded the motherboard, CPU etc. That wasn't to solve the problem but I rather thought it would have. I also replaced the surge suppressor, still kept rebooting. One day after installling a new modem I had the most spectacular show shooting out the back of my ps, a long cylindrical cone of sparks. A coil wire had detached in the power suplly and was vibrating on the other part of the wire. That had nothing to do with the problem though.. I detached the machine, took out the hard drives and put the boot drive in the Linux computer. I moved the previously 100% reliable computer into the place of the blown machine. I also talked to a lot of techs about the rebooting problem, but none could over any reason except to suggest there was something wrong with the electricity in the apt. I never noticed any anomalies like light flicker, reset clocks etc. so I didn't think any more alonf those lines. The 95 machine started spontaeously rebooting. One day after coming home from a bad day at work I popped a beer and for some reason the thought that these two computers all had one thing in common. The surge suppressor was plugged into the same wall outlet. I reached around behind my computer desk and the plug almost fell into my hand at the slightest tug. I plugged it into the other socket and the problem stopped. It might be something that insignificant.