I came home yesterday to find my 722 not on. It's about 3 years old and I use it heavily. I tried a hard reset and the fan would blow for a second or 2 and then the green light would come on but then go out after a little bit. I unplugged everything opened it up blew out the dust tapped a little bit on the hard drive and tried again. after a few tries it came on and I was able to transfer my stuff to my EHD. it's been on and working all night and today till I left for work. my question is can the hard drive cause this issue or could it be in the power supply. I'll probably go ahead and just buy a 722k , but I just want to see if it's worth fixing or selling. thanks guys for any advice.