Instead of opening new questions it's easier to add comments to the existing one so we can answer with something different to try.
Buy that being said the BIOS [b]CAN NOT[/b] be too lod to allow a compute to boot or allow a display however the BIOS Battery can go flat over time and need changing. When this happens you can get all sorts of screwy problems occuring though I've personally never seen one not produce a Picture but they will very rarely get much past the POST Screen and even then they come up with error messages telling you that there is somethign wrong depending on just how bad the battery has got. This can range from Time/Date errors to more serrious ones where the CPU & Ram is no longer stored in BIOS and needs to be reentered.
Start with the easy things test the monitor on a different Computer and make sure that the power plug is all the way in as sometimes these can be badly made and are hard to put in all the way.
If the monitor works then you'll need to work backwards from there swap out the Video Card if you have one and try in in another computer or swap the Video Card with a [b]Known Good One[/b] and test to see what happens.
If that does nopthing I would pull the M'Board out of the case and inspect it looking for breaks in the copper tracks any burn marks and buldging Electrolitic Capacitors these look like little tin cans standing on their ends and should have a Dark Blue/brown or maybe even a sort of red color plastic wrap with a + sign down one side generally in a white or at least a much lighter color strip as well as some writing in the same color but most of the time you will not be able to read it.
