you are only allowed to install it on one pc at a time so if you were doing things legally then you would delete it off your other computer and install it on the other . .well thatswht i was told in a topic a few months ago.
No problem doing this.What would happen if you bought a new computer,you would have to activate XP again when you installed it on the new one.It's just the same then on a second computer but problems can arise if you have to format the first computer for some reason and try to activate again.
When you buy a copy of WinXP it's the licence you're really buying - the CD itself, and any packaging represents a very small proportion of the overall cost. In the retail market there's no way of buying additional licences - you have to get a complete new pack - but there are several multiple licencing schemes for business users. In that context you pay for the number of 'desks'in your network. The corporate licencing schemes are complex, and they aren't relevant to your question.