Try shutting it off, disconnecting the adapter, and removing the battery pack for a few minutes and then re-installing the battery pack and turning the scanner back on. It should then come back up scanning and you can then shut it off and reconnect the external power and go back to scanning. (It sounds like some buttons may have gotten pushed whilst someone was playing with the external power and things just need to be `cleared a little bit' to get it going again.)
More likely the contacts on your programming port are bent and are torching.
Theres a hole on the right side labeled PC IF, turn off the radio, insert a paper clip into it to hopefully spread the contacts apart.