The only way it would improve your performance is if you were running enough programs to fill your ram and dump over onto the swap file. Do this..
Right click my computer
left click properties
go to advanced
click settings listed under performance
go to advanced
click "change" at the bottom under virtual memory settings
See how much space it is using, if none (at full load) then more ram will not improve your performance.
If you change the swap file size to initial size 768 and maximum 768, it will give you less lag if the system does use the swap. By not allowing it to increase or decrease the size, it doesnt have to find new sectors to expand the swap file to. Not giving you the nasty lag associated with expansion of swap.
Cancel out of that window and go back to performance options
under advanced click "by default, the computer is set to use a greater share of processor time to run your programs." Set this to background services. Because your windows services have plenty of room to run, your programs are allowed to max out the rest of the cpu/memory giving you a smoother overall performance.
The best way to backup data is by using a program like ghost (2003 or later), acronis, or pc-angel. These programs can create a compressed image of your entire harddrive small enough to fit onto a single dvd, or a few cds. Also small enough to be able to transfer and store somewhere else on the internet. If something were to happen, (even complete hd failure). You can still go buy a new hd and take the image off the cds and put it onto the new harddrive, in a few minutes your system was up and running as it was at the point that you made the image.