Quadra 840av hangs at startup. Cursor in top left corner

[mac-man6]

The Quadra boots to a grey screen with a cursor or mouse in the corner and does not continue any further. I can't think what it could be. I was swapped a hard drive and then stopped working after that. Right now I've swapped the battery, taken out the ram and disconnected everything except the power (floppy/scsi).

This beast must live on! help!

 

[mac-man6]

Attached SCSI cable to my HD and plugged in the keyboard and it worked. Gahh! Freaking SCSI gods, giving and revoking favour...