Series 2 540 grey screen.

I have a 540080 series 2. A few months ago the guide failed to up date. I rebooted the unit and it went to guided setup. After running through guided setup it failed to connect, kept saying there was a problem with the adapter. I tested the adapter in the PC and it is good. Years back I upgraded the drive to 250 but it ended up going south so I replaced it with the origina. lI assumed it was either the hardrive finally going on me now or the USB chip went bad. We hardly ever use it so I never messed with it anymore. I finally got around to messing with it again. I ran a phone line to see if it will update over the phone. It was on grey screen when I turned the TV over to it. I rebooted it and it goes to Welcome for less than a minute then grey screen. I tried to kickstart for a drive test but it goes grey screen before the yellow light comes on so I am unable to get into kickstart mode. I am getting ready to prepare a drive to replace the original. Does it sound like the drive or possibly the board or power supply shot?