Until recently, I too had problems with CTD due to my 'mod mix'....I had maybe 10 to 15 'must have' mods including MFM-Lite and ST. Naz Pens.
I am not all that computer/mod savvy but have been around here a long time and learned quite a bit about SHIII and how it all works together...or doesn't!
I finally decided to go thru all the steps get the 4GB patch working and ...
Lo & Behold, It all works now.
I strongly recommend you take the time to get the 4GB patch working...starting with an uninstall, then do the No Starforce/No DVD patch thing, then reload and set up the 4gb Patch.
BTW: I have a 32 bit Windows XP System with very similar specs to your computer.
Good luck to you sir...it's a real challenge to get it right but so WORTH IT once you get your favorite mod mix working!