Here is a new one for your records.
Couple of weeks ago i posted something about my laptop.
A friend gave me a Windows 7 CD copy. Luckyly it was for free. I installed and a few weeks later, it resulted that it was not a genuine copy. Now my laptop is getting so many problems from certificate issues, updates issues, etc.
I though i could resolved the problem by installing Windows XP which was the original OS that came with the laptop but i didn't have the CD. You mention that any CD will do it as long as i have the key. Unfortunately, I look at the bottom of the laptop where I should have found the key number but it's not in there.
Now, i look at the tiger direct website and they have some type of Windows XP cd but i wasn't sure if it was the right one and also how many computers i can use it for.
usually I have bought computer softwares such as Microsoft Office in which you can install them up to three computers I don't know if windows OS will come the same way.
I have this problem in two more laptops besides my own.
What are my options?
Thank you for your outstanding help

The solution is easy but may not be what you want to hear. You need to buy a copy of Windows 7 for each computer you want to install it on. I recommend for most people to just purchase the Windows 7 Home Premium Upgrade for $120 at the PX/BX. It's about the same if you buy it online with shipping costs. Anyway, once you have it, put it into your DVD player and boot from the DVD player. This will take you straight into the Windows 7 setup. When it asks for the key, enter the one on the box and you will be set. You can only install one copy on one machine. If you want to go cheaper you will have to use or buy Windows XP, or go free by using Linux. I like Linux Ubuntu as I think it's one of the easier flavors of Linux to use. Anyway, if you want Windows 7 there is no free way to get it unless it's pirated and Microsoft is getting better at blocking those copies. Just spend the $120 when you have the money. It's worth it in the long run as you know you have a good clean copy, or save the money and buy a new computer with Windows 7 on it. Either way, I don't ever recommend using a free or copied version of Windows as you could just end up with more problems than it's worth.

Well, I was thinking to get windows XP. The laptos are little old and I think i can sell them and buy new ones. My problem is that I can't find windows XP in which i can install it for all three laptops.
Thanks

That's what I'm saying. You will not find one copy of XP you can install for 3 computers. Each computer needs it own license. You can use the same CD to install on 3 different computers, but you need 3 different keys for each computer. Each key basically means you have a license copy of Windows on each different machine. If you have a CD label on the bottom of the computers then you can use that key. You would have to check to see what kind of key it's for though as there are different versions of XP. The key only works for the version it is meant for. If you want to run Windows 7 on the old machines but you are not sure if they will run on them, the try using the Windows 7 Upgrade Advisor. This will let you know if there would be any issues installing Windows 7 on the machine. If it passes you should have no problems, if it fails you have to look at each block as sometimes Windows 7 will still work but just not be able to use all it's features.

Again, if you don't have any CD keys on the CDs or on the label on the computers, then you will have to purchase a license per computer. That's just the way it is. If you plan on selling them, and you don't want to invest in Windows XP, then try installing Linux Ubuntu or Linux Mint on them. You may find out that they are very useful with Linux on them and Linux is not as hard to use as it once was.

Also, if you do decide to get Windows XP for the old machines, then I would suggest you check out eBay. That's probably the only place you will get a copy for not too much. Good luck with this.

update on this..
got a nice guy who loan me his CD, by this afternoon i should be able to install the original windows version that came with my children's laptops.

I will sell them and buy those mini HP laptops at the PX. They agree.

These have also the fake windows 7 and they are having a few issues as my dinasour laptop but they have less issues I have serious ones (because they are never versions)

Now, I heard about Komodo internet protection which is downloadable for free, I'm thinking to install them once i get the new laptops. what's your opinion?

Thanks for all your help.