patnuff:
I don't think it may help, still, can unsoldering everything connected be of any help?
Do you mean you have other components soldered to the I/O pins? I suppose there could be something interfering with the micro that prevents it from running correctly. If so then yes it may help, but try the reset first.
Also, yes there is a difference in keeping down the reset until it is ready for the upload. If you release the reset button too early then the bootloader could timeout before the actual upload begins. One more thing, you should pick a known good sketch before trying, like Blink.