I assume that you are using Windows XP.
Microsoft recommend that the optimum setup is to set a page file at least 1.5 times the size of RAM and locate it on a different physical (as opposed to logical) disk from the OS.
So in your case a Page File of 1GB located on D: would be the optimum setup.
It is also important to defrag the Page File regularly. If for some reason the Page File will not defrag completely then simply set the Page File to a very small size (e.g. 10Mb) and restart. Reset the Page File back to 1GB and restart. This will ensure that the Page File remains unfragmented for some time.