Need some fast-and-dirty Windows XP to 7/8 advice.

My kids’ computer blew out yesterday, and the spare machine we have floating around is running Windows XP. Is there an easy way to get it up to something functional, like 7 or 8? – Bearing in mind that I’m not a computer dude, I’m not going to be a computer dude before about 3:30 PM, and I’ve already thought of the ‘give my kids my computer so I can get a new one’ wheeze.  I just upgraded this sucker in… huh. 2015.  I could have sworn it was last year.

Two years old, huh?

:pause:

…No! Bad Moe!  Focus!

Anyway, I could use a little feedback on this one.