As a tech, I'd suggest one of the following is true: Your power supply is failing. Easily tested and cheaply replaced, but a possible culprit. Not likely IMHO, but possible. Your mobo is failing. My cabinet was acting the same way, except it would seem to be working fine minus the monitor and the keyboard. Like it was booting and not loading kind of... The power light was on, HDD activity was on, fans on, you could hear the HDD spinning, but no BIOS screen (the monitor was telling me it was unlugged), and the keyboard never responded. I replaced my mobo and the cabinet is working fine, even though the only component I changed was the mobo (same RAM, same processor, same HDDs, same video/sound cards, etc). In all honesty you seem to be exactly where I was before the mobo replacement. It seemed to need coaching (like holding the power button, leaving it off and unplugged for 45 mins, cmos jumpers, holding the power button for 90 secs after unplugging...) and one day it just stopped turning on with even all the gentle pushing I was doing.. You ca get a mobo cheap on Amazon that will slide in where your last one was... Just don't get a refurbished one.