I have a relatively new computer(about 2 years old), but for the past few days something weird has been going on. First it died during the middle of a gaming session, and then when I hit the power button to turn it back on, the lights and the fans turn on for about half a second, then the computer dies and doesn't turn on properly. But this only happens now after I've turned off the power(the switch on the back of my power supply) to it and wait for everything to turn completely off, then turn it back on and attempt to turn it on again. After that first attempt to turn on my computer's 'on' button doesn't do a thing.
The first time was about 3 days ago, but then I took a can of compressed air and blew everything inside of it(had dust bunnies the size of small mice) and afterwords it started fine and was running smoothly until my computer just died during the middle of playing a game(again), and is now in the state it is in now(again).
I've tried using more compressed air to blow out anything I had missed before, but it doesn't appear to be doing the trick this time, as it still refuses to turn on. Would this be a power supply issue do you think? Or is my motherboard dying(dead?) I've tried switching out my ram sticks also, but that hasn't helped any.
Power supplies and boards can fail at any time. Even expensive ones. I suggest you buy a known working power supply and try that first. It doesn't even have to be new. I find a lot of old antecs for sale; they're better made than some of the new ones, but only rated at 350-400 watts, which is enough to test your board.