The star power and ground distribution as posted by Adam Davies and Passerby is only a partial solution you must also:
Ensure the current capacity of the power supply is adequate for the peak power consumption of each bread board in use and preferably allow some margin of overhead.
Use decoupling capacitors as suggested by Joe from Ozarks
Use substantially heavier gauge wire for power and ground distribution as the other posters have suggested.
Finally if you get a sound 5v supply onto each of the breadboards and the circuit still doesn't work consider that there still may be one or more of the following to consider:
Clock distribution is not satisfactory between the boards due to the capacitive and inductive effects of the breadboard contacts.
Race hazards between signals introduced by the long leads and again breadboard contacts.
Depending on the 74XX logic family running the circuits at well below design voltage may have destroyed some of the gates. The latter tends to be more of a problem with CMOS but you don't give details of which one so refer to the data sheet.
Finally you state you're trying to run it at 640x480x60 = approx 18.4Mhz so there's is a pretty good chance of the circuit not working at all using those breadboards. If so run the circuit at lower frequency to debug the logic then solder a more compact version onto strip board.