i bought ezdrummer a couple of years back, since then i have changed computer. Now when i tried to register it, it said invalid serial number. how come is that?
Please do not confuse registering a product serial number with authorizing a product authorization on a computer.
When you register a product serial number to your Toontrack account, THAT is a once-and-done event
that determines your purchase of a product license.
Doing so provides you with 4 authorizations to activate on up to 2 computers simultaneously.
You should not have to ever re-register the product’s serial number again.