So my problem is that I've built a tower out of older hardware to run DOS/DOS games on, it has 512MB of RAM, its using onboard VGA video output, one 5200RPM IDE HDD, and one SATA DVD drive. Now as the title says it boots inconsistently, but not without pattern. I sometimes am able to continually boot/reboot it for days or longer with no problem, but other times it wont boot and I have to open it up to fix issues: which are also inconsistent. Sometimes popping out and reslotting the CMOS battery is enough, other times I have to unplug the power cable from the IDE drive, boot it, reboot it and it will be fine. Other times I have to unplug all hardware down to the RAM, including the CMOS battery and some onboard cables, boot it up and listen to the horrible no-RAM "beeeeeeeeeeep" for a few seconds, pull the power cable, replace everything and then it will reboot. Finally it ocassionally only requires that I move the various cables away from the CPU/cooling unit (at first I though maybe static interference) but then later after it properly booting a few times I rebooted, and tried to boot to a flash drive, and simply plugging it in while the machine was off was enough to stop it from booting.
BTW when I say "it doesnt boot" I mean the BIOS doesn't even initialize visuals, power management, or fan control. It powers on with a massive "VOOORRRRRFFFFFF" as the fan immediately kicks in at 4500RPM, never slows down, and the rest of the BIOS don't initialize. When this happens I often have to pull the power cable, as the interupt button refuses to hard-boot it while its like this.