I had the same problem, the ps2 keyboard would not respond and the computer hung at the bios splash screen. I removed my wireless usb mouse and rebooted. I heard some clicking while pressing the DEL key and after several Del key presses I was able to get into the bios setup. Pressing the F12 key several times brought up the Boot menu. I don't think I had to press the keys so often, the computer was just slow to respond. I made some changes to the bios and tried rebooting with the usb mouse but the system froze again. Removing the mouse alone didn't help I had to reboot with the mouse removed, which allows Windows to boot normally. This is such a common problem you'd think that Acer would address it.
Prospector, January 2010