Hello
I've been in this situation a while ago, and I found that:
- the BIOS POST sequence complains that there's no gfx card and beeps 3 or 4 times
- if the bios is set-up to ignore the absence of the gfx card it simply boots the sistem and everithing works fine.
The BIOS manufacturer for that system was Award, don't remember exactly what version , maybe 4,6 (i'm not sure, but 4.51 should work fine). I don't know if other os-es (non unix) can boot without gfx
The only disadvantage is that if you have some trouble with this "blind" computer, it is possible to be forced to shut it down, plug a gfx card and power-on again. Sometimes this is not desirable.