ADB Device Attached But Offline

[netspeedz]

Have an LG Optimus V that I can see attached using ADB, however, I can't really do anything with the phone because ADB reports back that the phone is offline.

Tried the ADB kill-server and ADB start-server commands. Didn't help.

Is there a way to put the phone back online so applications can be installed and the phone rooted?

Any help would be appreciated.