Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: How many Systems can you install onto?
Document: The product description told me (1) I could only install it on one 1 machine. That was ok. I'm ok with the license dying when the system dies. (2) It has to be a clean build. That's ok too. My systems got XP on it now. Win 7 NEVER upgrades from anything but Vista.So I was all set right? Not quite. This product comes in a sealed envelope  (you open it you bought it). The outside says you need OEM builder tools to install it even once on 1 machine.You go to the website to get the tools.
I've already done a test clean retail build using the retail install DVD I "borrowed" from another of my systems.. I just can't find a way to BUY another retail license so I can ACTIVATE it!I never would have ordered this product if Amazon had told me EVERYTHING I would have to do to install it. I'm returning the envelope  unopened to get my money back.I couldn't find any other way to get a copy of Win 7 so I gave up and REORDERED the OEM product again. This time I IGNORED the info about OEM builder tools on the outside envelope, hoping everything that I needed would be inside.
Early on the install asked for RAID drivers. I had found them on Highpoint's website for Windows 7 and loaded them onto a USB thumb drive. I browsed to the USB drive and the Windows 7 Install picked up the drivers and went right on an installed the OS successfully.This old XP business machine is seeing new life with its shiny new Windows 7 OS. It seems to run faster over all than it used to. It definitely does not run slower. I am very pleased with how well this install worked. And, we can take advantage of the large RAID secured storage space on our home network as well as having an upgraded Windows 7 computer.
I was very pleased to be able to update to Windows 7 from XP Prof.  instead of Windows 8 at this time as many of my programs would not work  with 8 and the expense of replacing all of them at this time was too much.
After many years with Windows XP I cannot help but wonder why Microsoft changed the program...obviously to sell more products. I have had Windows 7 for about 2 weeks and am finally becoming comfortable with it.
My office suite was removed during Windows 7 installation I am not able to add it without buying another program.For the moment I can keep my present laptop without too many changes needed.Yes I would recommend this program to someone who was using a old operating system.
I have been using Amazon.com for many years now. I read the description but  upon installation, Windows would not allow me to activate Windows 7. I called Microsoft and they told me that the product key on the package was reported as invalid!Microsonot refuesed to sell me a product key online or provide a way to purchase a cd online.AND of course there is not way to contact Amazon that I can see.PLEASE DO NOT PUCHASE THIS ITEM!!! !
They say we won't be protected by security - oh really?How many run Spyware, Malware and Antivirus software on your computer?Have you had a problem with security? even if you didn't update your system, your anti-everything ware worked just fine, didn't it?So why do they lie to us?Just so that all are aware of, Windows NT4 through to Windows 8.1 have the same Kernel.NT4, NT5, NT5.1 NT6 NT7 they all have one thing in common - same kernelNT5 (win 2000) NT 5.1 (XP Pro) NT6 Vista and so on.Apple and Linux, they upgrade their Kernel.The main security is in the software you put on your computer - but that isn't what Microsoft would have you believe.
Barely compatible with video card in desktop, but Microsoft walked through the transition with the use of the Windows 7 compatibility checker at the Windows web site.I chose Windows 7 Professional because of it's expected longevity, familiarity of the various Users with Windows 7, and with the expectation that it allowed me to hold on to the desktop for at least another year.I used the Windows 7 Upgrade procedure which involves choices on how many of the Windows XP files and programs I wanted after transition. I made the choice to subscribe to Microsoft Office 365 after I completed the Windows 7 upgrade.The User experience has been very positive.
EDIT:Changed to 1 star, since that's what people look at the most:Do NOT buy if it's coming from "Big Buys". I've bought several copies recently; anything coming straight from Amazon is legit, but I got couple of couple from Big Buys that were definitely pulled from other systems. This has caused me two issues up front: it's hard to avoid ripping the CoA sticker when removing it from the shrink wrap they use. One of the keys had to be activated over the phone. In the long term, I get the added benefit(lulz) of possibly having these keys deactivate sometime in the future.Sorry for assuming people didn't know how to key in some numbers and letters.
Answer: Legally one. Honestly 100s