Sounds like virtual memory call using a register.
Sounds as though you've altered the size of the swap file and win can no longer find a component it needs.
How much physical memory do you have on your machine? If it is 256 or 512 then you can turn off virtual memory. I always do and note a huge performance increase anyway.
Try
here for some performance tweaks.
Turn off VM and initilise windows within RAM and it should solve the problem.