Too Much Power!!

OK, I have an Arduino UNO that i accidentally supplied too much power via the power plug (18V). It worked and then it got hot and stopped working... I know im sorry.. lol (next time i will use an external regulator)

Well, im ordering another one but i have a soldering iron and wondered if I can find the faulty electronic part (regulator.. etc) that might be bad and replace it. The power led is still on when it plugs in but it doesn't show up on the computer... if that helps...

I also noticed that the 117-5g rc018 chip only has two legs soldered.. is this normal or did the middle pin break off? (this is the part that got hot i think)

The 8U2 is toast == fun surface mount soldering. Watch out because power adapters tend to put out 1.41x there rated voltage. This means the "18v" power adapter probably put out over 24v which toasted the regulator rated at 20v which shorted and took the 8U2 with it.

I was reading this forum... http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1294106073

I still have power to the 5v and 3.3v while using usb... do you think i can just replace the 328p and it will fix it? Or is the other atmega chip gone too?

Either way i will get another arduino uno and first check the old one with a new chip. If the other chip is bad that controls the usb interface, can i program it another way and use the arduino embedded in a project?

dls13dls: I still have power to the 5v and 3.3v while using usb... do you think i can just replace the 328p and it will fix it? Or is the other atmega chip gone too?

I can pretty much guarantee it.