Boot disc loads yet keyboard not respond

Hello, My Acer Aspire M1640 gave me the BSOD, either due to a virus or interupting it during a reboot using the power button. Anyway, I can get into bios and my computer responds to keyboard input; however, as soon as I place a boot disc in and it says press any key to boot from cd/dvd it will not accept any keyboard command, I pressed almost every key on my keyboard and it would not do anything. I know my keyboard works, the num lock light and shift key light come on - please help - thanks so much - oh it has vista home edition basic, also it I tried using system mechanic and it would not show the C: drive, but does show that the hard drive is there in bios.