Windows XP License

Before you spend money on more licenses, you might want to do a little digging first.

The Tech support consultant may have purchased an Open License, in which case your client WOULD have only the one License. Was this License turned over to yourclient?

If he used only a single standard license, I'm surprised all the computers could be activated (or have they?).

How many licenses (and what type) was your client charged for?

Depending on what your client was charged for, you may have a civil case against this consultant. At the very least you could turn him in (or threaten to) to Microsoft.

The bottom line here is that your client is now responsible for proper licensing, no matter who did what.

With XP, the only way to re-activate/re-register with a different license number/software key is to reinstall.

Before you do so, if all the computers have been successfully activated and are working okay, I would follow the maxim of "If it's not broken, don't mess with it!" If you ever get audited, the auditors will be more interested in whether you have the required number of licenses, not what the actual numbers are on each computer.