Hey hellsown,

The computer should be fine for 5boxing on it, and I would recommend Windows Vista 64bit, for hte following reasons:
1) Symlink advice above
2) You state you ahve 4 gb of physical memory. This in combination to the video memory would be in excess of 4gb, which means it is impossible to use all of it in a 32bit OS.

Windows Vista 64bit is really a great operating system, I use it on all 5 of my computers. It was designed for NEW computers, and you want to ENSURE you have up to date drivers. Beyond that you shouldnt' have much issues