2 computers "died" recently. Coincidence?

[dandy_48103]

Something seems to be killing my computers so I hope to find the problem. Please help.

My 4 year old Emac. computer died about 2 months ago. and its replacement died today.

Facts:
The first machine cut off one day so I turned it back on but it behaved kind of erratic from then on i.e. 1 hour later the mouse and keys stoped working. I pulled the plug when this happened but it just happened again shortly after for the last and final time. Afterwards when I would press the power button, the computer wouldn't post at all - nothing but a black screen and no beep codes. Hard drive seemed dead as nails. Actually, the power supply seemed to be the only thing working and btw I tested the power supply with a tester and it passed fine. And I replaced it too to be sure.

I really could care less that I lost my emach but 2 month's later, today, the same darn thing happened to my other computer (very clean 5years old) which was substituting for my first. Now this is getting scary. Is the problem my wall socket? It doesn't seem faulty because the lamp plugged into it seems stable and doesn't flicker in and out or anything. Could the problem be one of the parts interchanged from computer 1 to computer 2. The parts both computers had in common are keyboard, mouse, monitor and hard drive.
P.S. I was just reusing the harddrive as a second drive for more storage space. And, all my old files were in tact btw.

My own stupid guess work:
1) My monitor is an Emac with a broken button - kind of pushed in permantly - and it needs to be pressed in just right to make work.  Hmm, maybe this broken button issue is real serious causing a short or something frying components or draining my cmos battery :-?. Should I toss it?
2) Maybe the hard drive from my emach had a virus that now got passed on to the second computer. I did run virus protection on it and all seemed fine. Yeah there was some supspect files, but the program supposedly took care of that.
3) Btw On computer 2 I noticed the powersupply (450watts) was a little lose at the screws. Nothing too bad, just something I noted. Is this a big issue?

Any insights into this recurring problem? How can I ensure that computer 3 will last a bit longer? Can I safely interchange parts like cpu, ram etc?
thanks so much

[compEngineer0]

as far as interchanging parts go, that's a maybe. if the parts are good and working (and compatible) then go ahead. but if they are not then I would be reluctant to stick them in a new computer... the monitor should be a non-issue as well as the power supply screws. just in case on computer 3, leave the old hard drive out until everything is running stable, then add it in. it might just be bad luck twice in a row, but set up computer 3 (new or old?) and try it out with as many new parts as possible. none of this stuff sounds like a problem, but give computer 3 a try.

[ale52]

Do you have your system on a battery backup?  Just because the lights don't flicker doesn't mean you don't have power problems.  Computers work on a level much more sensitive to voltage changes than lights.

It's cheap insurance to get one of these things.  I live in the foothills and have all my important systems on a battery backup as the power here is pretty flakey.

Alan <><  

[dandy_48103]

Thanks for reply folks. Here's an information update. I took both computers to a computer store for analysis. Motherboards are gone and everything else was fine though I can't say for certain on the hard drives; they weren't inspected because I kept them to myself as I didn't feel safe handing over all my data.

Anyways, I bought a $6 outlet tester and even though I foolishly said power was stable, I did find two power issues when I finally got back behind my bulky workstation.

1) The computer plug going into the wall socket was not secure. The plug could slip in and out so effortlessly it's like you couldn't even feel tension from the wall socket. Even worse it seemed I was incapable of touching the plug gently enough to NOT interupt the power going to the computer.

I have no power back up on my system to answer earlier question.

2) Now, the killer, the tester showed "open ground" , so my computer wasn't even grounded. Actually the grounding was ify depending on wether or not the plug was jiggled in the socket  just right   . My guess is it wasn't.   I don't know for sure but I would also think that without proper grounding my surge protection can't work. Sound right to you?
 
Conclusion, so I'm pretty sure the home outlet destroyed my computer. But as always I'm open to any insights on this, because even now with the outlet repaired, I feel like I have some sort of post traumatic outlet syndrome or something.  So, I'll appreciate any confirmations or rebuttals to my conclusion. I just want to learn with a longer lasting computer #3. thanks

[TomTW]

I thought you posed some interesting questions; and well written. First off, it sounds like your experience in these matters; is likely more extensive than my own; that being said, I’ll venture my observations, simply as food for thought.  
I myself use CyberPower 725SL backup primarily to keep from loosing data on power outages; which just the other day happened six times in one afternoon and as a backup against power surges. From what I’ve read it appears most PC or motherboards have some sort of internal surge protection built in. So surge protection is just a backup measure.  
In any case; the point about the open ground at the wall outlet, poses a very interesting possibility. Sorry to say; it appears that since the case, the PSU, and the motherboard etc share a common ground; (being that it is an open ground, or no ground at all) any static electricity coming into contact with the metal case from any source, would contact those other components as well.
The metal case is a good conductor; and being ungrounded static electricity would naturally be absorb by it. So it seems, your PC may not have been damaged by a power surge; but rather by the chain of event; so to speak.
I’ve read that static electricity can damage internal components and that we can carry a static charge without ever noticing it per say.
One reason this post interested me; I’m trying to help my brother, work out some power supply issues long distance. I keep asking myself, what made his HP Pavilion power supply go bad… Now I’m wondering if he doesn’t have the same problem with the wall outlet; though his house is less than a year old.
I mean what are the odds.
Anyway, good luck with your third PC.