Missing OS and Shutdowns

[Invictar]

Hello,
So recently I had a spree of missing operating systems using vista, during my checking of the connections and cleaning the case (first place I start always) I see all the fans are in operation and then checked the sata cable. Side note noticed the vid card was running super hot so swapped the card for a older one I have and still experienced random shutdowns and the occasional missing OS.

So figured diferent card heat seems okay, I had some power flicker issues a few months back and thinking I corrupted some OS files during that. So I went for upgrade to windows 7 with a reformat booted up fine loaded antivirus software then loaded google chrome as soon as it started install it would power down, then typically say Missing OS a few reboots after. Now I am running a chkdsk /r hoping to see what it comes up with but this has really stumped me. New OS and the upgrade had the reformat option, tho it went so fast I have a feeling it did not reformat lol

Anyone have any thoughts on Missing OS and random power downs

 

[Invictar]

Lets see if this stumps the community hehe

 

[Invictar]

some more info, seems installing anything tends to power it down.
Currently looking into a bad stick of ram, not sure this could cause missing OS messages on boot up and installing/usage causing the pc to power down but anything is worth a shot lol

 

[Timop]

What PSU do you have?
Try running a scan of the HDD also, using HDtune or whatever the OEM has.

 

[Invictar]

ran a memtest and chkdsk /r with nothing detected so far. Power is fine that was a old issue in the house that is resolved now (was on a battery then but you never know)