Help OC Core 2 Duo

[F1N3ST]

Well, I have great tempatures, 25C at idle, 30C at load using speedfan, on stock intel heatsink/fan. My motherboard is a POS, allowing for a 266 or 333 FSB nothing in the middle. A 333FSB is only a mild overclock, and i'm sure that it can take it, but when I boot overclocked, my monitor is black, and I dont ahve onboard graphics, so idk. All the fans run and everything, its just....weird. My graphics card is a 5500FX(For Now). (PCI)