Without the battery, the BIOS settings must be reset each time the host is booted. Information, similar to the sort of hard drive, the boot order, date and time, is saved in BIOS and is used by the host when it is booting. AGP slots accommodate video cards with additional capabilities and PCI specific playing cards to attach host bus adapters for expanded storage and cards for added USB and Firewire ports. If you have an intel processor with its personal fan, it may be that you didn’t push the fan screws all the way in. If it isn’t all the way in which in the motherboard will not send a sign to the screen/won’t even boot to bios, to guard the cpu.