Late 2005 G5 Dual ran fine till I tried installing more RAM. Now logging in with my password just brings back the blank log in page. Replaced just original RAM, but still no go. Tried zapping pram, tried command-option-O-F to reset svram(?), tried Command S, tried pushing button on logic board, tried putting in target mode to repair disc using my old laptop, but nothing makes a difference. System profiler shows it recognizes the RAM, so they're in the right slots and properly seeded. In target mode, I can see the hard disc contents, but the aps don't open when double-clicked. Any other thoughts of what else I might try?