onboard? if she has 4gb of ram, probably 2x2gb of ram? meaning it will still have 1 stick. and you dont need an opitcal drive to boot lol
almost every board does
given her outline of the problem I would also suspect possible gpu malfunction.
booting from onboard with only one dimm of ram is a pretty standard step in attempting to deduce where teh malfunction lies by process of elimination.




