512mb pc133+windowsxp=problems

Okay, I just ordered new ram, 256 mb pc133. When I
installed, Windows XP would just stop on me to the
BSOD and say some error like
Page_File_In_Unpaged_Section or some errors like
that. I was thinking it was just my virtual memory that
was causing the problems along with my low disk
space. I changed the VM to 384mb from 768mb. It still
had the same problems. The computer will stop, say
some error, and say some suggestions like Change
ram or change video card. This might help, one of my
ram sticks is two-sided and the other is one-sided. I
don’t know if it matters if both of the ram having two
sides or just doesn’t matter. All that matters is that I
need help. Please