I just got a Power Macintosh 6100/66 in a lot of computers off of craigslist. When I first powered it on, I got the chime but got no futher (no video). I switched off the computer and turned it back on, trying to reset the PRAM. The gray screen came up, and it chimed a second time. The happy mac appeared and it just stayed there. I heard the hard drive "knocking" so I figure the drive's probably toast. I powered the machine off again. Now I'm back to chime, no video and no boot. I've unplugged both the hard drive and CD-ROM and reseated all the SIMMs with no change in behavior. Any ideas?

Thanks,

Greg