My mom recently bought a malfunctioning computer (Dell Inspiron 530) from a friend for $25 thinking I could fix it. It had freezing issues and would randomly restart. I reinstalled windows and things went well for a couple weeks. Once in a while it would restart and get stuck on the very first screen, the one that shows the Dell logo and the options to get into the BIOS. (setup, boot menu, etc) But pressing any of the indicated keys did nothing. I couldn't get to the boot menu or anywhere other than that screen. The only option was turning the computer off and back on and then it would boot properly. Today, it decided it wasn't going to boot at all anymore, even after turning it off and back on. It stays on the first screen and does nothing. I researched a little bit, took the computer apart, and did a step by step trouble shoot. I cleared the CMOS, unplugged the CD drive, the card reader, and the hard drive, took out the ram, and even the modem, and nothing worked. I'm thinking it has to be the processor, motherboard, or power supply. I would like to replace the faulty hardware without taking it to a computer repair person. Any idea what it is that's causing this problem?
Is the CMOS battery dying? Might try changing it if you haven't already. A dead battery will keep you from booting.
Then breadboard the system with the mobo out of the case sitting on an insulated surface. Install just the CPU/HSF, 1 stick of memory, PSU, and connect the monitor. See if you can boot to BIOS by shorting the 2 pins the PWR button plugs into. If not try a different stick of RAM. If you can be sure the memory sticks are OK, you either have a bad board or CPU. My guess would be the board.