right long story cut short

my pc had a problem, meltdown gave it to a guy in the paper. Paid like 48 quid for it all to be done.

Before handi had windows xp home edition. I thought he would put that back on as i gave him the ORIGINAL disc.

Got pc back alls ok. He has installed XP proffesional. I try to get updates and now have been told by a message from Microsoft i have maybe been a vctim of piracy.

I tried the guy, and his number is not in action

So what can i do? Microsoft want 92 to update. Yet i have original home edition. Can i simply upload over the top or not???

Dead worried.