Is a backup an alternative to having no Windows installation CDs?

That said, however, is making such a backup basically the same as the recovery disks that most pre-built computers come with?

How about getting away from Microsoft altogether and start using the great, free Open Source programs?
I am running Ubunto on my laptop, use OpenOffice.org with its excellent programs and have Firefox 3 as a browser and Thunderbird for e-mail. And all for FREE with excellent update support. Think about it when Microsoft knocks on your door for a $ 100+(or more) for its next OS!

Although Leo addressed one method of data backup, most of us have computers well modified and can't go back to a pristine state.
However, there is another option, not requiring a backup immediately after you get a computer; one that allows the image backup to take place at any time. One that can be used to boot the system even if you current hard drive fails completely.

What I use is a product called BounceBack. It images your entire hard disk (all partitions) and then maintains the backup continuously and automatically.
In the event of a complete hard drive failure, the backup hard drive can be remounted as Drive C and you can pick up exactly where you were when the original disk failed. Plus you have a current copy of all files should a virus wipe out the Hard drive. Or, you can simply boot from the backup drive (in my case it's drive J).
It's an all-in-one solution to disk failure.
In the case of not having installation disks, having a complete, current image that the computer can boot from is a much better solution than going through a complete reload of the origional operating system and programs and all the custopm settings.
In my specific case, I use a 2nd hard drive located in the optional drive bay of my laptop, but the drive could just as easily be located on the USB bus.
Here is the URL of the products:
http://www.cmsproducts.com/index.htm

I recently found Macrium Reflect. This runs free of charge for a reasonable evaluation period. After that, the full registration is about $55.00 Australian. This gives you the option of backing up specific files, or creating a ghost image of an entire partion. Used in conjunction with Microsoft's own back up tool, this makes an effective recovery startegy. It's saved me once already after I deleted some critical client files.

Ok. I can backup everything in my computer, but what if mi whole hard disk crashes and I can not buy one equal to it?
I have to use this backup to restore on the new hard disk, and this hard disk has more size than the first one.
Can tools deal with this? I mean, can I use tools to restore a partition on a bigger one or I have to restore the partition as is and create a new one to fit the whole disk?

My son gave me his laptop (HP). When trying to "bot up" it comes to the end of the line and says, "No Operating System Present". I tried several times to boot up with Ubuntu but there is no recognition of the DVD drive as if it weren't even there. I tried to change the boot preference and that didn't work either. He has no disks since a friend originally gave him the laptop. I have tried everything I know. Please help.