Sonar LE serial number problem

Hello friends, I have problems with the registration of Sonar LE, which came with a TASCAM 1200 audio card. When I add the hard disk of my computer I use it only to work with the recording programs, with a Windows 7. In This hard disk only works the Sonar LE, but when I put the serial number, install it and change it for another, I do not understand what happens, since the Sonar is installed on another disk that has the PC that I use sporadically to not Have conflict. Can someone tell me what to do? ...... Excuse my English.