Well, first things first - have you done this before? You need to ensure that you don't bend any pins and that you put them back in the correct way around!
Do them one at a time, ie power off, remove one, check all pins, put the ROM back in, turn on, see if the fault has been resolved - if not move onto the next one - repeat.
This may not of course fix the fault, but it's worth trying as a first easy measure.
Here's a pic of a KoD boardset:
The ROMs that you need to try are all of the large black ones - eight of them in that pic, the ones without labels.