Upgraded CPU, Intermittent start-up problem

Hi all. I recently upgraded the CPU in my Acer Aspire 3050-1150 laptop to a Turion XL-56. The first bootup was a breeze, and Windows Vista Home Basic recognized the new chip no problem. Temps ended up being cooler than before the upgrade.

Later that day, attempting to undervolt, comp just shut down. I tried to reboot...comp started but shut off a second or two into loading windows. Next boot attempt the on/off switch wouldn't work at all...appeared dead. I waited a few minutes, took out the AC adapter and windows booted. Next time at bootup, similar pattern, but wouldnt boot even with the AC adapter taken out. This time it booted with the battery out and AC in.

Similar pattern at every bootup...false starts, shuts down at various points, but then eventually boots up after several attempts. I have just been leaving it on, in sleep mode when not in use. I am very afraid of doing a windows update which requires a reboot, so I haven't been doing that. I reseated the CPU to make sure all connections were in place and that the heatsink was not too tight on the CPU.

There is a barely audible single beep followed immediately by the faint 'click' of the power switch shutting off. The beep is so hard to hear I don't think it is a BIOS beep.

Any ideas?? Thank you all.

 

Bump......Any ideas please?