IPhone can't be synced because it can't be found, what's the problem?

I have tried all the options from the other question of this. However, none of them have worked.

The exact message "The Phone "Will's iPhone" can't be synced because it can't be found."

I'm running OSX10.6 Snow Leopard and iTunes is latest edition 11.something.

I have tried:
-restarting and restoring iPhone
-restating laptop, unistalling iTunes, reinstaling, and installing earlier editions.

Factory reset while its plugged in