|You should try to boot your computer from your windows cd, which will initially bypass your hard drive and allow you to regain control of your machine.|
Here's a very basic list on how to do it.
1. turn off your laptop.
2. insert your windows cd
3. turn on your laptop
4. when your laptop first turns on, you should briefly see a black screen with some technical information on it regarding your BIOS. It will say something like: "Pheonix BIOS" or someother brand of BIOS, and show the version number. If you don't see that screen, I don't know what to do for you.
5. make a note on that screen of what Keyboard key you need to press to enter your BIOS settings. It is usually something like "F2". You will have to push that key quickly before your computer tries to boot up Windows.
6. If you have succeeded in pushing the key in time, before Windows tried to boot, then you will enter your computer's Bios settings. If Windows comes up next then you know that you have failed to push the key in time. Just restart your computer to try again. There is no harm in pushing the key repeatedly to make sure you've got it.
7. in Bios settings find the options for "Boot order". I can't be more specific, as bios's differ. It will usually show you 2 or three devices numbered 1,2,3. etc. That is the order that the BIOS checks your devices to find a working operating system to boot. Normally, that is found on your primary hard drive.
8. In that list of numbered devices, change the FIRST device in that list to "Cd" or "DVD". We want the BIOS to check your CD drive before checking your hard drive for an OS to load.
9. save your Bios changes and exit the BIOS settings utility.
10. The computer will now restart the boot process, only this time, it will try your CD/DVD drive BEFORE it tries your hard drive. It should find your Windows CD now and boot from it, thereby allowing you to repair your Windows installation, or do various other operations. If you are unlucky, there is the possibility that your CD may not be "bootable"; that it is just a regular CD with a bunch of files on it and that will suck for you. If that happens, maybe you have a friend who has a bootable windows cd?
11. You can leave the BIOS settings the way your changed them or change them back to the default settings with your hard drive listed as #1. If you leave them with #1 as CD/dvd, but you don't have the cd in, the BIOS will just go on to the next device anyway.