iMac keeps crashing - please help

Got a four month old Intel iMac 27".

Yesterday when copying some pictures from my camera, Preview crashed, then again, then the system. Ever since I can't even open an application without it crashing. Sometimes I'll click to log in, get a blue screen and then sent back to the log in. Sometimes I get in and finder won't boot, most times I can click on something and I get the black shadow with the multi-lingual "Your computer needs to be restarted" screen. I restart, same stuff happens

I'm new to Macs so don't have a clue where to start. Unfortunately I never got around to the Time Machine backup either.

Please help!

That darkish screen with the many languages is a Kernel Panic. A lot of times it's caused by a hardware fault. Did you install any after market RAM in the iMac? Let us know and we will go from there.

No I didn't