Overvoltage i/o pin fried my arduino uno. Can it be saved?
It's hard to definitively say, but I wouldn't be surprised if the whole thing is toast. There are a few things you can do to check. Look over the board for any visible scorch marks or popped caps, anything physically damaged.

With the atmega removed, plug the board in. You might try plugging it into something other than your laptop to start with. Something with a solid 5V output, like a wall to USB charger for a cell phone. There's enough other stuff on the Uno that, even without the Atmega, you should be able to discern whether things are working properly. Get a multimeter and probe around testing voltages. Make sure that +5V pins are actually at +5V and +3.3V pins are correct as well. Feel the board (carefully) and make sure nothing is hot. That's a sure sign that things aren't going well.

If that turns out okay, go ahead and plug the board into your laptop without the Atmega. Check if your Arduino IDE or any serial terminal program can still recognize the COM port. If it does, I'd say you're probably in luck and the board may be ok.

Lastly, if everything is successful, you can try putting the Atmega back in. I wouldn't hold my breath about it working, but it isn't unheard of that just a single I/O is fried.