I’ll stand corrected on this if I am wrong but unless you are using ram render, in the options the ram render of which you say 1024 is available should be set to 0. By setting a figure in this box what you are actually doing is allocating ram ‘only’ for ram rendering and hence take that amount away from what is available for your ‘proper’ render.
Set your pagefile to twice the amount of ram you have. Place your pagefile on a different drive to your system files & ideally a different drive to your render files. Place at least 100mb of pagefile on you system drive.
Set your pc to Clear PageFile at Shutdown
Go to Start > Control panel > Administrative tools > local security policy > Local policies > security options then find the option >
“Shutdown: Clear Virtual Memory Pagefile” right click then Properties + enable and then hit Apply button. This will increase your shutdown time but it is better to start with a clean slate.
Have you configured your ram properly? I know nothing on this subject apart from you cannot just ‘plug and play’ more than 2gig of ram on windows. You are on windows xp sp2 yeah?
No heat problems?
Good luck!