So here's my situation and maybe someone who has had a similar experience can help me out.
I had just moved recently and my desktop was running fine prior to the move without any issues. When I had first set it up after the move it was also fine and not giving me any problems.
On the second day of use in the evening I was trying to plug in a USB device and it didn't seem to be recognizing it or responding to it so I tried a reboot, and then after the reboot my machine now hangs on the POST screen with the progress bar at around 10%.
This morning I tried taking a few pieces out to see if I could figure out what was wrong. I disconnected all of the drives and pulled the video card out and powered it up and it made the six beeps to indicate that the video card was missing which was good. I also checked all of the connections internally to make sure no power cables or the like seemed loose. Upon powering up, the system made it past the post and tried to boot from the CD drive which was empty at the time. So I powered down once more, reconnected the hard drives and booted up again and it failed to POST once more. I removed the hard drives again and it still failed to POST. I remove the video card once more, booted, shut down, put it back and booted again and still failed to POST. It now refuses to get past the first portion of the POST it seems regardless of what I do. I've rechecked all the connections, tried booting one DIMM at a time and all of it seems to have no effect.
There were also a couple times when I powered the system up and it started to boot, then it seemed like it powered off mid boot and then started booting up again. I'm starting to suspect that the power supply is the problem but the power supply test button doesn't indicate any issues directly. I've tried different power outlets in the apartment so it's not a wiring issue within the apartment itself.
Unfortunately I bought this system two years ago so the warranty has expired and tech support won't give me the time of day without forking over cash first.
Has anyone ever experienced something similar?
I had a similar issue to this with some pos HPs at work. It turns out the P4 connector that goes by the processor was bad and it wasn't putting out enough voltage to the CPU which caused a "fatal error" on the HP system. If you can get someone to lend you a power supply, i would definitely try that first. You can always pull the CMOS battery, hold the power button for 10-20 seconds, put it back in and see if it'll POST.
Related to what Necropotence mentions ...
If not using a good UPS Battery unit on the machine ... it might not be getting enough power (amps). Re-install at old location that has working power.
As an update, I did manage to get my system back online although I'm not 100% sure on the root cause at this time. I had tried resetting the CMOS during the week and it didn't seem to have any effect at the time. I had left the system idle until the weekend and then when I tried powering it on for the first time it prompted me with a CMOS error/notification and I had to reset the system settings. Once that was done however the system seemed to boot up fine and has continued to do so since.
There was also a brief loud noise from one of the fans when I was starting it up that first time and I'm wondering if perhaps there was a stuck system fan and my cleaning prior to the bootup on the weekend alleviated that issue which prevented an overheating lock-up of the system. Unfortunately I couldn't identify the location of the sound before it stopped and it hasn't re-occurred since.