I looked, and there was no obvious way to delete a user account. It's possible to work upwards from the "basic user" status, or downwards to ban any user for a predetermined or unlimited time, but I didn't see any obvious way to just delete one. (not saying there is no way... just that it may be buried behind a couple layers of fail-safe measures that I am not hip to)
I'd agree with the above... just leave it inactive, it won't hurt anything... then later on when ya get another XJ someday... you can hop right back onto the boards.