The PIC does not start its program.

[skimask]

I think you've certainly covered the bases on what NOT to do with a PC board.
....
Throw that one out. Get a new soldering iron, some 60/40 solder, some liquid flux, and a large pencil eraser. And try again.

It might've been easier to show the GOOD solder joints and the 'finer' points of this PCB.
Nothing like a properly tinned, properly cleaned, fully dewetted pad with a proper concave fillet between the lead and the pad connecting the 2 parts...
I saved those 4 pictures and I sent them to the instructors at the 2M-CCR class I took last year as examples of what NOT to do.
(BTW - I saw 2 pads that would pass at that 2M-CCR course as 'acceptable' in the upper left corner of the 3rd picture, the rest....fail.)