OK, I managed to flash the unmodified BIOS by putting it on a USB and booting and pressing Ctrl+Home on a PS/2 keyboard. Relieved I don't have to mess around with LPT->SPI cables I'm a bit nervous to try flashing the modified BIOS again though as it didn't appear to have any problems flashing before so I imagine the same thing will happen again if I try it. EDIT: Would it likely be any better flashing the modified BIOS with the MSI HQ forum USB Flasher?