Background story made short, it's a Dell Dimension 9100. It is a little over four years old. Yesterday, I put 2 x 1GB sticks of RAM in it to add to my 2 x 512MB sticks, to give me a total of 3GB. The computer worked fine after this. Later, I went by CompUSA and picked up a Seagate 500GB SATA hard drive to replace the hard drive in my PC. The PC still booted up fine, but obviously without an OS since it was a blank drive. However, upon trying to install an OS, my PC kept telling me that no boot device was found. It was then that I realized that a few months back, my CMOS or whatever had this oddity where for some reason, it no longer saw my DVD drive, even though both Windows XP and Debian 5.0.3 saw it and used it perfectly fine. So, in order to try to fix this, I took my DVD drive out, and changed the jumpers on it from Cable Select (factory default) to Master since it's the only IDE device in my PC. After putting the jumpers in the right place (and I'm positive it's on there properly) I put the DVD drive back in and connected it all back up. Reconnected my PC to power, monitors, mice/keyboard and etc., and went to power the PC on... nothing.
My PC acts completely dead. I can't get it to power on anyway I try. I don't think anything is wrong with the power supply, as when I plug the cable into the PSU a green light on my motherboard lights up. I also don't think it's the motherboard as nothing changed between the time before I changed the DVD jumpers and afterwards. I did a little bit of research on my G1 (a pain being a phone) and some of the results I had suggested a USB port was causing a short. I've heard of this before so I tried out that method, but all of my USB ports look intact with the black piece covering all of the pins. I proceded to make sure it wasn't any other ports such as my ethernet port, but they all seem fine.
Other results that came up suggested that other owners had this problem, but that it wasn't the motherboard or the PSU. At this time, those results didn't have any kind of fix.
I tried talking with some fellow PC guru friends to see if they could think of any solutions, but we weren't able to come up with anything. I know 100% that all of my connectors on my motherboard are properly connected and that nothing got knocked loose during any of my upgrading.
It seems I have the EXACT same problem this guy had, same PC and all:
However, I don't exactly understand what they did to fix it. Can anyone dumb it down for me? I don't have a multimeter and being 17 with no job and just having bought PC stuff, I can't afford one.
Also, I did a power supply test with a paper clip where you put one end in the green wire and the other in a black wire, and my power supply turned on fine, so it isn't that.
Thanks in advance for any help!