I think if there is any kind of critical timing involved here, I would be removing that regulator as it's dropping ~7v or more all over the top of that there PIC and directly heating it. Now that really can't be a good thing...
Either find a better one, or at least move it out of harms way.
Clean up the board properly, as stated earlier, it's a mess.
Check all your joints are sound and short free.
Check your power supply is correct pre and post regulator, I'm assuming it's a 5v reg, so you should see at least 4.95v on it's output, if not investigate why.
If that proves fruitless, check that the oscillator is running, those pesky little cylindrical crystals can be a pain sometimes.
Check any reset circuitry is correctly operating and that the PIC is not being held in the reset state.
if all appears as it should, check other things like capacitors fitted properly, especially the polarity concious ones, check resistors for open or high resistance, track continuity etc.
hope this helps
rgds