Are there problems even on 32-bit Windows systems like Windows 7 Starter and XP?  I had a demo version on disk (not run through the system installer) and it wouldn't start.  I'm wondering if I could use it at all or if it would just cause problems for the system because it's older.  Thanks!

A proper version, properly installed, runs fine on WinXP and many succeed on Win7 too. The latest version of PA9 is PA9.03 It truly is old - PA9.03 was last supported by Cakewalk on WinME.