Computer going into standby mode for no apparent reason.

Skeith

Okay, here's my situation. A few days ago I moved from one island to another, which necessitated having my desktop tower as checked baggage on the short flight over. Of my options I decided that that was my best one, and when I got a look at my computer, I noticed a ding in the case but no internal damage as far as I could tell (very shallow ding, not visible)-- cables were where they should be, nothing was loose, etc. Yesterday, I started having this strange thing happen. My computer seemed like it was shutting down (monitor went blank and the backlighting in my keyboard turned off), but when I would hit the power button to turn it back on, everything would be as it was right before it went under. Steam windows were open, brower tabs, whatever I was watching on Netflix was right where I left it. Any ideas on what this could be? I've run rkill and Avast and it's not a virus or something, since it happened as I was booting the computer up this morning after the scans. I looked at the temps for my cpu and motherboard and they were normal. In total, this has happened 4 times.

edit- oh, I also gave it a thorough dusting after the first time, just in case. Windows 7 if that makes a difference as well.

Dark Raven X

What were you doing when it went to sleep? Does it do it if you leave something like VLC player open and paused?

Skeith

The second and third times were while I was watching Netflix. The first time was idle on the desktop with a steam chat window open along with programs that I always leave running like Rainmeter. The fourth, the one this morning, happened during the boot process. I was getting dressed so I didn't see when exactly it happened, I'm assuming during or slightly after the "Loading Windows" message and Microsoft logo, but it also shut all the way down that time. It didn't happen when I was playing Civ 5 or L4D2, which strikes me as odd, since the computer would be under heavier load I'm assuming, especially with a late stage game of Civ.

Enc

I hate to ask this, but did you check windows to see if the power safe settings are shutting off your display after 10-15 minutes of idleness? My laptop reads steaming video as being idle, and will power down in this fashion turning off the display to save power but not the hard drive. While L4D and such would have you constantly working with your input devices staving off the shut down.

Skeith

My screensaver kicks on after 10 minutes of no input from the keyboard or mouse, and my display is set to go into powersave after 20 minutes, so I move the mouse a little every couple minutes when I'm watching something. The computer itself is set to never go to sleep. This happens totally out of left field.

Enc

Hrm. Only other thing I've encountered like this was bad ram, but I'm far from a expert in hardware.

The Crowing One

Bad RAM sounds a decent explanation. Something going a bit wonky with the power supply could also be a culprit.

Skeith

I'll give memtest a shot, but how would I test a power supply? I don't have any tools for electrical work, nor the money to purchase them.

The Crowing One

I'm no expert, but I did have a power supply fail on me a few years ago. It didn't die completely, but it would suddenly force reboots and shutdowns. Turned out it was either damaged or just wasn't up to the task of my hardware. I don't know if there's a specific test, but it can usually be determined by process of elimination, as RAM is easy to test and settings are pretty simple to check.