CastleLink on Windows XP will not Open

[TexasSP]

Never had to use Net Framework on my XP machine and have the latest version on it as well. I use it on both my XP (desktop) and my vista (laptop) with no issues.

I know on Vista to install it I had to click "run as administrator" to install properly but never had this issue on XP.

May be obvious but have you done a complete uninstall, delete, re-download, the install? If not try running as administrator and see if that helps. Maybe a newer windows update has caused an issue in XP as well?