Avast or Microsoft Security Essentials for continuing XP

[Iknownot]

Windows 7 has an XP emulation mode for applications that want Windows XP... give that a try with your apps...

Yeah. Wish that would work. Would have saved me a lot of expense and headache.

Win 7 emulation mode is pretty poor with specialty crafted XP software.

I think you missed the part that it's legacy software AND a subscription to an online course. It would need to be connected to the internet.

I guess that I did. Get a Win 7/8 machine for the online subscription and run the legacy software on the PC completely disconnected from the internet. Laptops are cheap enough now that spending the $400 will be less of a headache than a hijacked machine you really need to run a specific piece of software. (or maybe he could even borrow one to complete the online course). IMO, at least.