If your system is slow with XP, its not going to improve with Win7. Win7 is very much like Vista only slimmer or just to say, cleaned-up abit. Overall, Vista does well on any system that can support it. The same advice applies to any OS. If your h/w is getting old, the new OS from MS have proven to be resource hogs until finely tuned in time with the expert advice and true meaning of makes the OS get along. So think new system if you can afford it to reduce new OS headaches as it readily supports the new OS and capable to expand as well should the need arise. You can try the Win7(on old system) and install it and go from there and allow experience dictate your final result.