Windows 7: Window 7 home preimum cracked or real?

Hi. I recently got a new computer from someone (not from a store), he said he reformatted the computer.
I forgot to ask him if the window 7 is cracked or real or not.
How do you know if window 7 home premium is real or not?

Additional question.
I was installing Window service pack 1 and after the update, it asked me to reset for additional update or something.
I restarted and it says its updating 1 out of 2 and every 20 or 40% of update, my computer would just restart and continue installing where it left off.
This continuous restarting happened at least 4 or 5 times. After that, it was finished and said welcome and I was finally get to log in.
Is it normal or what?

Jason, welcome to Sevenforums

Check it by clicking this validate online link: http://go.microsoft.com/fwlink/?LinkId=203870

It is not normal that the computer should restart multiple times during any single update, although that does not necessarily mean that your computer is cracked. Mine has only ever restarted a maximum of 2 times due to multiple updates being installed. You may have installed multiple updates, also.

Hmm. since I got this computer couple of days ago, I am installing 5~8 updates per restart. Is that why?

Exactly as he said^ but also right click computer and select properties. Then look near the bottom it should say windows is activated with a product id, and the sticker to the far right.
Here is what mine looks like
and yes it's normal although 4 or 5 restarts isn't the most common.

This is what mine looks like

I am almost positive that it is not cracked. If it is a laptop you can flip it over and match the Product id in that picture with the sticker underneath the laptop. Even if they are not the same, Windows is detecting the os as active and genuine. So no worry's my friend even if it is cracked, it is detected as Genuine. Try matching the product id sticker on the physical shell of the computer if you really want to be sure.

Just a little extra below
Also this is not required but, on that computer look for something called hp support assistant and open it click "maintain", and then click "refresh". It will show you if some updates are available. ex:driver updates.
Another not required, but if you search in the start menu "ccc" and find a sort of red icon Download this to automatically find amd or ati driver updates AMD Driver Autodetect

Most Windows 7 activation cracks work by modifying the MBR or "volume boot sector". Replace them with the default ones and check if still activated.

From recovery environment->command prompt

The only way to know definatively is to generate the MGADIAG report. Follow the steps here:

Windows Genuine and Activation Issue Posting Instructions

And then post your MGADIAG report here and I'll take a look for you.

Regards,
Golden

From the info given so far it is not possible to guarantee the authenticity of the Windows OS. A later post gives the definitive answer!
Also I would strongly recommend that you don'rt install third party so called driver detectors, they are more trouble than they are worth. This is Window 7 we are talking about not XP. Windows 7 is the best guide to correct drivers. Work on the principle "If it ain't broke, don't fix it" That's better than "If it ain't broke keep fixing it till it is!" That all IMHO, of course!

I don't understand why your calling them third party. Technically they are, but they come preinstalled on the computer. They are from the official website, and really It is not needed, but why not just use what they give you to update your computer to its latest and probably most responsible state. It's not like i was telling him to go use driver genius or anything like that. Please correct me if i am wrong, but i have used Amd's official driver updater on multiple pc's and no problems have occurred. Hp support assistant comes preinstalled on the computer and so does CCC so why would it hurt to use them and update your computer?