Resolved Random shutdowns

I have come into an Acer Aspire T690 running Win 7. It is a decent computer and I would like to use it for something. Unfortunately, I have discovered that it shuts down randomly for no obvious reason. So far shutdowns have occurred at different times under different circumstances. I can find no obvious pattern. The shutdowns are instantaneous. The computer immediately turns off completely, with no warning and no attempt to save data or anything else. When the computer is restarted, there is no sign that anything was wrong. I don't get the usual Windows error message that occurs when the computer loses power. It simply boots normally.

These shutdowns remind me strongly of RAM problems in the old days when a computer would instantly power off if a bad bit of memory was accessed. I don't know if something similar is going on here. I did run the Windows memory test and it reports no errors. Does anyone know anything more about this? Can this have anything to do with Win 7? Is it likely to be some kind of motherboard or other hardware failure? I would like to fix this if possible, but I cannot use the computer as it is.

 

Thanks, that's a good suggestion. I will look into it.

 

I replaced the psu but the problem didn't go away. Then I discovered that the cpu was running very hot when under load. I put a thermal monitor on it and it shot up to 85 degrees while streaming before I shut it down to prevent damage. TJ max is 90 degrees and it would have easily hit that if I let it keep running. So now the question is what to do next.

I realise this is no longer a Win 7 issue but it is an area I don't have a lot of experience with as I have never been into overclocking. If anyone can point me in the right direction I would be grateful. After that I will close this thread.

 

Are all the fans working especially the CPU fan, are the vents clear of dust.

 

Great minds think alike. After some contemplation, I did exactly what you suggest before seeing your post. I vacuumed out the considerable dust that had accumulated in the heat sink vanes, cleaned off the old thermal compound, which looked pretty dire, put on new and reassembled. It is now running steady within the recommended temperature range even when both CPU cores are at 100%. Thanks everyone for the help. Now I have another question but I will post that separately.