My understanding is that it will only recognise up to 3.5gb but probably only 3gb of RAM.
in Microsoft's words....
To avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB
Just go 2+1. On a cheap 8 year old PC you're not going to notice a huge difference anyway.
Oh, and please do us a favour and don't fiddle with the PAE switch if you've been reading things on the interwebs.
