Well, you'd better not try to press the current XP installation into XPMode: that's not going to happen.
Get a real virtualization tool like VMWare (Server, Player 3, Workstation) and try to import the XP install into a virtual machine (either local or remote though the network, then both should be same cpu-brand AMD or Intel). If that works (ymmv, did it several times, but not always successfully), run the VM and see if all is well (turn down the memory setting for the VM by about 50% to be able to start it properly) If all still is well, store the VM and enhance :-[ the PC to a clean install of Win7, install the VMware product you used earlier, and run the VM if & when needed. Presto! you're done :Thmbsup:

The real question ofcourse is: Do the improvements warrant the upgrade-price? :-\

And added to what Stoic Joker says, an extra qualifier could be that the comment has the best/most useful new feature request of all comments posted :Thmbsup:.