I have a desktop computer that I built myself about three years ago. Off and on over the past year and a half it has stopped getting a signal to the monitor. I've struggled to figure out what the problem was many times, but eventually I would leave it off for a few months and it would magically work again the next time I tried to turn it on. I haven't the slightest clue why. Anyways, now it is doing the same thing again. I power on the system and I immediately hear the fans running extremely fast and they never slow down. Usually they start out fast and then settle into a normal speed within a second. There is no POST beep or anything, but the monitor won't get a signal from the video card. I've removed various components (RAM, graphics card, etc) to see if they were the issue, but nothing has changed. I disassembled the whole thing and it put it back together step by step, testing it after connecting a new component, but still nothing changed. I've tested every cable I can, the only conclusion I have been able to come to is that the PSU is going bad (giving off too much power?) and I need to replace it, but I don't want to spend the money on a part that doesn't need replaced. So I need to know for sure. I have a multimeter to test it, but I am not entirely sure how.
Has anyone had a similar problem that can also offer some solutions? Any help is appreciated.
It's most definitely either a Power Supply or a Motherboard issue.
The Power Supply is a more likely candidate, especially because of the "leaving it off for a few months and magically working again turning it on afterwards" part. This can happen for many reasons... but an incident like this is likely to be Power Supply related in my experience.
I would suggest you try a different Power Supply to confirm this first... have you got a friend or someone that can perhaps lend you one to test?
You can also buy a Power Supply if it's refundable to test this out and return it later if it's not the problem.