Reply To: Trouble Comes in Threes
I recently went thru the same thing with the power-up cycling. Most threads seem to blame this on maybe corrupted files on a HD, but the power-up time before reboot was far too quick for the hard drives to be involved.
I finally traced it down to was a new scanner I had installed. This is a USB connection, and if the scanner is powered up then the computer will not boot successfully. FWIW, the scanner is an Epson V500, and I tried it on several USB ports, both V2.0 and V3.0. The MB is an Intel DP67BA.
This particular MB never has been able boot from a hard drive or thumbdrive on the USB ports, although it is supposed to.