cod 4 problem

so my cd key wont work anymore becaus I bought a new computer and then the cd-key didnt work anymore because it was registered on a different computer
what to do :/ sorry if i post it here

umm is ur key legit or pirated?

I've changed PC 3 times and always used the same key, there shouldn't be a issue. If there is, I would suggest a format

@above is correct.

You can use the same key on multiple pcs. You simply cannot PLAY on multiple pcs with the same key at the same time.