well its come down to this. i took out 1 ram stick and it worked with just 2gb ram. I took out the one working and just put in the other one. and no chance of it booting up. So its a faulting ram stick i gather!
Im going to ring apple tomorrow and see if they can send out a replacement? (do that even do that)
I tried the one that is working in all 4 slots and it boots and everything as normal.
I just want to re install SL, but when i hold down the option key nothing happen it just takes me to desktop?