Macbook Head scratching problem

Hi, I am I like to think that I know a bit about the workings of computers (pc's) but i am quite new to macs and have a problem that I cannot fix.
I Droped my macbook the other day and it wouldnt boot. I got a blue screen with a ?. I thought it was a hdd problem so replaced it . After doing this The Macbook wouldnt even turn on so i opened it up and had a look. It now turns out that the only way that I can get the macbook to turn on is to disconnect and reconnect the "bios" battery. It will then turn on automaticaly when the power leed is connected without pressing the power button. The installation cd will boot up but I cannot use the keyboard/touchad pad to take the installation any furlther. This obviousley made me think that it was a problem with the Keyboard/touchpad but after connecting a usb mouse and keyboard I realised that the usb ports wernt workin eilther.
The only thing I can think of is if there is an onboard driver problem or somthing. If it was a pc i would look at the bios.
I know I will prob be wrong and my spelling is **** but any help will be most welcome.

Thanks