Hello, I confess I'm at the end of my tether and also realise that this isn't a new problem or indeed a unique one. I have pretty much tried every bit of advice that I've found on the web thus far. I've reinstalled Snow Leopard, reset the PRAM, repaired the drive in Disk Utility and repaired permissions, reset the SMC, started up from the install disk and started up in safe mode. I've even completed a 35 pass secure erase of the hard drive. None of that has worked, if anything it remains on the blue screen longer?! When the 'Welcome, Bienvenue etc' music played at the start of the fresh install, it was blue screen all the way. The computer in question is an iMac 4,1 1.83 GHz Intel Core Duo. I'm aware this is an 'old' machine but I'm trying to make it work for my father. It does eventually work but after a considerable length of blue screen time! Any fresh help and advice will be gratefully received.