Windows XP on multiple computers

[compnovice]

I have a valid XP home upgrade version.
I put the copy also on my kid's PC.
I am now building a gamming rig for myself.

How many time can I install XP home Upgrade version?
I am already running into activation problems on my system.
Microsoft says I have exceeded my limit for that product key.

What are my options ?
( Please no lectures about Linux or Macs )

 

[Frank4d]

You can install one copy legally on one machine. You are already over the limit so the solution is to buy two legal copies, one for your kids PC and one for the gaming rig.