Short version - Sony Vaio VGN T370P - 4 years old - got a virus - couldn't clear it (don't remember name) - did a restore from partition D, still had a problem - did a restore from CD, virus cleaned. Installed all current drivers, checked BIOS, etc - everything works, EXCEPT when I plug in a projector the notebook freezes (the computer recognizes the projector and the projector shows the image fine, just frozen) - Talked to Sony tech support and installed some more recommended drivers - same problem - sent notebook to Sony repair, they said "motherboard, $700" - I said "easy excuse, no"
Again, everything works fine EXCEPT when I connect a projector (which I have done about 500 times before) - same reaction when connecting an external monitor.
Want to take a shot? I would be indebted to whoever gets this figured out!