Checking if microchip or software is broken
From my extensive experience of screw-ups and facepalms when building up circuits for PICs, if the chip still programs and verifies successfully, you're probably ok.

The problem you're having is in your code. Here's a list of probable causes:


You don't have configuration bits set, so the FOSC bits are running as default. The default FOSC on an 18F4550 is an external clock. Unless you actually have an external clock connected to OSC1 (which you probably don't), your program won't execute.
The watchdog timer is default to on, which means it's running and constantly resetting your chip. It should be disabled in the configuration bits.
You have no infinite loop at the end of your code. Without an infinite loop, the program will reach the end of the program space and reset the chip. You can do something as simple as putting "while(1);" as the last line in your main function.