Blank screen booting problem

My laptop won't boot. I tried reinstalling windows by inserting the os recovery disk. However, when I was asked whether custom or upgrade and I chose upgrade it just said that I must restart the computer and let it start normally because it was booting from the cd. My problem is, my PC isn't giving me options to start normally or default, etc. Once I turn on the laptop, the BIOS would appear, the CMOS error would prompt (but this already prompts before and my laptop still works, so i think changing cmos battery won't solve my booting problem) and then there will be a blank screen with a bar blinking on the upper left for about 3 seconds then it would disappear. What happened? What should I do? I don't care what data would be lost I just need a computer to use.

What is the CMOS error? If you have a recovery disk it should not ask you about custom or upgrading. If you want to re-install Windows, do a clean setup, remove the existing partition, create a new one, and have setup install it on that.

A blinking cursor at boot can mean a bad hard-drive.