Hello,
LabVIEW 5.0 is not officially supported on Windows XP, as it was released before XP was released. However, it will most likely work, other than a "Wrong OS" message that you may recieve during installation. I have successfully installed LabVIEW 5.0 on my XP machine and not run into any trouble. However, you should be aware that issues you encounter may not be supported. Please see these KnowledgeBases on our website for more information:
http://digital.ni.com/public.nsf/websearch/93661E9632363E7186256D12005FC9C2?OpenDocument
http://digital.ni.com/public.nsf/websearch/E001E0210C5D259686256CE9005832D0
I hope this helps! Have a great day!
Liz Fausak
National Instruments