I'm not sure if this has been posted or not before,but here goes.
If you use the old analog CH Pro Throttle like I do,do NOT upgrade to Windows XP if you want to continue using Speedkeys.
Speedkeys won't work at all,and Ch tech support verified it for me.
The only workarounds I can think of are to make a second bootable partition with an older version of Windows,or to add a second bootable HD as a slavedrive with an older version,which is what I spent last night doing.And that may not work with an older motherboard...I can't say for sure.
Just a heads up for everyone.