Can't start Windows :(

Well I have P4 2.26 and Abit BD7II - Raid mo/bo.
Then I have 2 sticks RAM one PC2100 CA 2 and one PC3200 CA2.5
I tried to use 3:4 stting with all the loosest settings for RAM and I can complete MemTest in DOS but I can't get into Windows. I always get a BSOD and it restarts
But how can I complete MemTest and not get into Windows ?
I use Win XP and I upped VDimm to 2.7 ( max for the board )
Any help would be appreciated !!!
Thanks in advance !!!

well have you tried just using one stick?

Yeah I used the 3200 one but I really need 512 MB. Unless I'm using so much my HD swaps as hell

Did it boot in XP with one stick

yes it did! As a matter of fact it can boot with any of two sticks but not at these settings ( I never tried PC2100 alone on these settings )
Right now they are at 140 FSB 1:1 at 2-5-2-2 without any problems. I just can't upp FSB any higher because of bad cooling