Steam games problem

[arc@css]

Hi,
I had installed on my system the episodes 1 + 2 of Half Life 2. I uninstalled them, now sold them, but apparently they aren't able to be installed on someone elses PC since they are still registered to my steam account. How do I get round this please?

Thanks.

 

[arc@css]

Ok chaps, thanks, will just have to refund the guy.