I recently bought some new RAM for my 4 year old G4 that was running very slow. I found that the sleep function didn't work properly after it was fitted and when woken up, the fan spins but the screen remained blank and stubbornly refuses to do anything - I have to force a shut down and restart. There were other issues too like the CD-ROM drive door refused to open. I cleaned everything up using OnyX and this has resolved everything but the Sleep function - Any bright ideas...? BillM