I did the exact thing you're trying to do about a year ago, however I have an HP Pavilion (won't buy another one) computer that is only 800 MHz, 512 RAM. I ran the compatibility check (from CD and web) that showed most of my hardware (printer and scanners-all HP) as well as some software (not Poser or 3D apps) would not run on it. The best thing to do prior to upgrading, if you go that route, is to do the compatibility scan, print the list out, and go to all the sites for your hardware/software and download XP patches for them. Once you've upgraded your system (you have the option of saving your earlier OS if things don't work out), you can patch everything. Some software may need to be uninstalled prior to the upgrade and then reinstalled after. One program in particular was Microsoft Office (2000). You would think of all programs this wouldn't be an issue. Once you've got XP installed, when you run some of the XP patches a box may appear saying it isn't compatible with this version of Windows or is unsigned or whatever. Generally you just click OK and continue with the update. I haven't had any problems with XP other than a few program hangs and that stupid box popping up asking me if I want to send the info. to Microsoft. Occasionally I do if I'm online at the time. Windows ME is a piece of crap, although on my slower machine it seemed to run faster. XP is more user friendly and seems to fix things by itself instead of user interaction.

Poser 2, 3, 4, 5, 6, 7, 8, 9, 10, Pro 2014, 11, 11 Pro