Oc'ing Dells is a long, painful process, I think NoAffinity knows the thing, but heres what I remember...
1. You remove the RAM and boot up the system.
2. Let it POST and do its beep sequence.
3. Turn off the system once the beeping is all done.
4. Re-instal the RAM.
5. Boot up system and you should be in the ADVANCED BIOS settings.
I'm NOT saying that this will work for sure, but I heard it a while back that you can get a few advanced settings by doing this... But since no one on this forum has tried it, We'll never know whether I'm helping some loser spread a crappy rumor, or if I'm doing good for all the Dell users out there.