Windows 7: External hdds caused computer not to boot

This is a strange problem .Last night, I wanted to put the computer to sleep, as I always do at night.

The mouse was frozen and the keyboard Sleep function didn't work.

I thought a reboot would solve it, but upon restarting, the computer would not boot.

I went through the Repair Option, Safe - nothing worked.

I decided to do a System Restore with an Acronis Backup image, and that also failed.

I thought I might have a bad hdd, and was starting to shut down the comp to replace it, so I unplugged the external drives and all of a sudden it worked. ( after reboot I ran full Diagnostic test and it is fine).

Any idea what could have caused this - BTW : the hdds are now plugged in and everything is fine.

After I unplugged the hdds and rebooted, my CPU went from a normal 5% to 75% - now back to normal.



Last thing: after I rebooted last night, I put the computer to Sleep, only to have it wake up on its own - that problem is also corrected.

I am wondering if a component is starting to fail - hope not, this comp is only 3 months old.

Thanks,

Paul