I have tried searching the forums for other reports of this problem, but maybe I am not looking for the right terms.
I have a desktop that was apparently custom-built. It was bought from a friend we have done business with for years. The cabinet says, "HP Compaq." It has an Intel Pentium 4; the speeds of the dual processors are 2.80GHz and 2.79GHz. RAM is 1.50GB. It was recently upgraded from Windows XP SP3 to Windows 7 Ultimate (32 bit).
We have a similar HP desktop from the same source - therefore probably the same motherboard - which does not have the problem.
At completely random times - no one application or website seems to trigger it - it will suddenly stop and go into reboot, coming up in the BIOS screen that gives Windows restart options - Safe mode, Safe with networking, etc. There is no "BSOD" at the crash and if there is any system log taken I don't know yet where to look for it.
Sometimes it goes for quite a while without doing it, but in the past couple of days it has done it several times - at least twice today, once less than an hour after the last restart.
It had this problem under XP also. The upgrade to W7 was done because of Microsoft's announcement in April 2014 that support for XP was ending, not as an attempt to end this problem.
Is there malware out there which is known to do this? Is this a frequent HP or Pentium problem? Any ideas?
(F.Y.I., you are talking to a software person, primarily. I was trained as a mainframe programmer, and also have done technical writing. I will probably recognize a lot of terminology, and am aware that system dumps and logs are often wanted when diagnosing such things, but would appreciate instructions on where to look for such things as log files or dump files. If there is a Tutorial somewhere on such stuff, let me know.)