Computer doesn't power up properly
Something is obviously wrong with my computer lately, but I can only speculate what. What happens is that when I turn it off (or something turns it off) I often can't properly start it back up again even after trying many times. Sometimes I am lucky enough to start it up after I unplug it completely and then plug it back in for a few times and trying to turn it off and on in order to get to the normal boot (and even then it seems it just doesn't prompt CD/DVD devices for boot at all).
When I turn it on at these occasions, fans start spinning, the green light turns on and one CD light turns on, but keeps being lit up (which isn't normal) and nothing else happens. The picture doesn't come to the monitor and the boot sequence doesn't start.
Yesterday it was so bad for so long that I even carried it for a quick check at a computer service, but the guy there saw my graphics card not entirely plugged into the slot, pushed it in harder, tried it out and it worked. Well, today I'm getting the same problem and all cards are pushed in properly, so it's not it. It probably worked for him randomly, as it does for me at home.
I was suspecting my power supply because it is an old one (came with the case) that can sustain about 200 watts, but the computer didn't originally had an extra DVD player, a PCI DVB card and a graphics ATI card with a fan on it. So I'm guessing that maybe the power supply just can't supply enough energy to it all, which manifests in these boot failures.
But then it's weird how it doesn't restart itself at all. I heard that when the power supply is too weak, computers actually restart themselves occasionally too..
Anyway, I'm wondering what could be the problem. The service man said that these things could be caused by anything from a MBO to the graphics card to the DVB card. I doubt it's a graphics card as its new, so it might be either an MBO or that weird SkyStar DVB card.. or.. the power supply..
If you've had any experiences similar to these I'd be glad if you'd share it.. Thanks for your help.