Haks,
That info you gave this afternoon may be quite useful. If it lasts much longer under light usage (e.g. on the Internet) but it only lasts 20 minutes under heavy usage (e.g. video-intensive gaming), then another possibility is that it could be your graphics card overheating. You say that, when the screen stops receiving a signal, that it takes a few minutes before you can get it back on - that might be as long as the graphics card needs to cool down a bit. It all adds up.

But, whilst the graphics card would seem the most likely suspect if there's an overheating problem, there could also be other culprits. Video-intensive gaming also makes the processor work a lot harder as well so these also got hotter and might cause the same symptoms if they overheat.

Replacing the graphics card may only cost you as little as a power supply .... unless you want to fit a high-performance card with lots of power.

However, if you can borrow a monitor off of a friend for the day, then you could confirm that your monitor isn't faulty without spending anything. That's probably the route I would want to take first.

Anyone else got any suggestions other than that it might be the PSU, processor, graphics card or monitor?! Shall we have a vote on it?!

Yea i think your right, my graphics card is the problem. Ill borow my friends monitor but i dont think ill fix it. Ill might as well buy a new pc. Mines getting kinda old. Thanks for all your help guys

Okay, well hey no prob bud. Before buying a whole new PC, I suggest trying to just upgrade your current one as much as possible. Your choice though, chief. Have a good one!

I just noticed that the ai coming from the fan is quite warm. Im not sure whever it should be but i just thought id say.

i have the same problem of no signal but power was fine b4 i changed the heatsink.I've already replaced mb, cpu and tested monitor on another system. What else could it be?i dont wana spend more money till i'm sure.

emmsicle,

Please start a new discussion to ask your question rather than hijacking another members discussion, thanks.

From the D-A-L forum rules

Please do not Hijack other members posts. For example, if you are browsing the forum and see a member has posted a question with a problem very similar to your own, PLEASE DO NOT post in the same thread and say "I have this problem also! please help!"
Instead simply click the new thread button and ask your question in your own thread. There are a ton of reasons for this but the main one being that although your problem sounds the same, it will most likely require a different solution.