I'm assuming direct USB?
Anyways, I would guess that if you uninstall and reinstall ti-connect, it will work. If you are on a 32 bit machine, then you can completely uninstall ti-connect by following the instructions in that tutorial the squidgetx mentioned. Sometimes the drivers get a little screwy. (You can even uninstall the drivers on a 64 bit machine, but so far, I don't think any one has had any trouble with that.)