This might seem like an odd place to ask this question, but here goes. If I replace the XP home edition on my computer with XP Pro, will I then have to reinstall Poser and all my other programs , or will they still work?

When you first begin to install xp pro it will probably ask you if you want to keep your old settings if you click yes for that most of your programs should still work. I don`t know which version of poser you have but I know that poser 4 still works even after reinstalling windows 98.

Installing a new operating system should make no difference at all to other programmes installed. The operating system is purely concerned with the operation of Windows not the other software. The only way changing the operating system would mess up Poser is if you tried to downgrade your operating system to something like Win 3.11 because it couldn't run Poser! This is just my opinion and no guarantee is given or implied ;-)

Best to wipe your drive clean before installing WinXP Pro. This goes for any modern OS, PC or Mac these days. Updating/upgrading instead of replacing will bite you in the rear later on.