Sony VAIO VGN FJ 1z/w

Hello everybody i`m new on this forum as you can see,I bought myself a notebook Sony Vaio model VGN FJ 1z/w second-hand so I`m wondering how can i make it more faster than it is (it has an extra 512mb of RAM)what windows is more recomandat for this kind of device windows xp what version home pro x86,x64 or vista home premium home basic ultimate x86,x64?i got now windows vista ultimate x86 version but it`s slow takes a lot of time to enter the application so what would you recomand me?what`s best for my notebook?
PS:Sorry for my bad english..

i have 1.5gb of RAM but aero style doesn`t work I ain`t got any areo style and I think it is because it haves only 1.5gb and it needs 2gb as I seen from microsoft site

<2GB of RAM of vista is a choke, and I'm willing to bet that you've got some programs running in the background you don't need. Try using the msconfig utility to reduce your memory usage on startup.

Here's a short intro:
http://netsquirrel.com/msconfig/msconfig_vista.html

if you mean does msconfig work in Vista x64, the answer is yes.

The only real difference between Vista x64 and x86 is x64 can address lots more memory. There are some driver/compatibility issues with x64, but they're not that great. Any notebook that can run x86 can run x64. I recommend x64 to anyone, simple because it's more advanced and allows you to have more memory at your fingers in the future.