In the comments to an earlier post, TJ asks a question that I get frequently:
my sister got office ultimate 2007 and was wondering if i can install it on 2 computer?
The short answer is yes, but the longer answer is probably not in the way you think. The license for all versions of Office 2007 except Home and Student edition are very clear. (To view your license, open any Ribbon-based Office program, click the Office button, click Word Options, select the Resources tab, and click About <program_name>. For Outlook, click Help, About Microsoft Outlook. In the About dialog box, you’ll see a View the Microsoft Software License terms link.)
For any retail edition of Office 2007, the details are in sections 1 and 2:
1. OVERVIEW. These license terms permit installation and use of one copy of the software on one device, along with other rights, all as described below.
2. INSTALLATION AND USE RIGHTS. Before you use the software under a license, you must assign that license to one device. That device is the “licensed device.” A hardware partition or blade is considered to be a separate device.
a. Licensed Device. You may install and use one copy of the software on the licensed device.
b. Portable Device. You may install another copy on a portable device for use by the single primary user of the licensed device.
This is actually a pretty customer-friendly policy, in my opinion. If you have a desktop and a portable PC (or two portable PCs), you can install and use the software on both devices. But those terms apply only if they are your computers, where you are the "single primary user." Under those rules, installing your sister’s copy of Office 2007 Ultimate on your computer would be a violation of the license terms.
For an OEM copy of any Office 2007 edition, the option to install on a second device is not available.
Office 2007 Home and Student Edition has a separate license policy, which allows the software to be installed and used on up to three computers within a single home for noncommercial use. If you and your sister live in the same household and you are not using Office for business purposes, she could get that edition and you could indeed install and activate the software in full compliance with the license agreement.
Update: In the comments to this post, Serdar has this follow-up:
One tough question I get asked a lot which I have no answer to: What constitutes "business use"? If someone has a home business or is self-employed, do they need to buy the business editions of Office?
The relevant portion of the license agreement for Office 2007 Home and Student (section 2a) reads as follows:
You may install one copy of the software on three licensed devices in your household for use by people who reside there. The software is not licensed for use in any commercial, non-profit, or revenue-generating business activities.
If you are self-employed, the license terms clearly do not allow you to use Home and Student Edition on your work computer. For that, you need to buy any other edition. [Update 2: Except an Academic edition, as Peter Ortner notes, correctly, in the comments.] If you have a home business that is truly a business, then the same applies. Everyone has to read the agreement and decide for themselves how it applies. My personal opinion, not given as legal advice, is that the reasonableness test would say you could use this for volunteer tasks on behalf of a non-profit (as long as you weren’t involved in the day-to-day running of the organization). And I think the same test would say if you occasionally sell something on eBay or take an occasional writing job for which you get paid, that’s OK as long as you don’t consider it a business but a sideline or hobby.
Frankly, I’m happy that the license agreement doesn’t try to spell out this line in excruciating detail and leaves it up to the customer to make a good-faith decision about abiding by the license agreement.
Ed Bott (@ wordpress.com) 
One tough question I get asked a lot which I have no answer to: What constitutes “business use”? If someone has a home business or is self-employed, do they need to buy the business editions of Office?
Serdar, good question. I have updated the post with my non-lawyerly opinion.
Thanks for your update. I had the feeling this was the case, although I hate having to make hairsplitting EULA decisions like this at all.
Microsoft Academic package products are marked “Not for use in a commercial environment”. To quote from the Office 2003 EULA:
I understand that the definition of Qualified Educational User varies by region. 🙂
In that instance, one would need to buy any other FPP or valid Upgrade product (i.e. not an Academic Edition product).
This is off-topic but since you’re answering odd MS questions.
I have some friends that use the Action Pack to get the PCs in their homes licensed for all the MS goodies. This will work for up to 10 PCs. (client OS and appwise) MS has made the hoops for getting an AP a little narrower but they’re still fairly leniant.
A Technet Download subscription is only 50$ more a year though and you’re able to use all the licenses you want for ‘testing’.
Which do you feel is the better way to go?
Les, that decision is most assuredly personal, based on a variety of circumstances. But in general I can note that the big difference is Action Pack licenses expire (legally, not technically) if you allow your subscription to lapse, whereas TechNet licenses are good in perpetuity.
You can run your business on Action Pack software and not run afoul of the license agreement. TechNet software is licensed for evaluation and testing only.
In my office, I use TechNet and MSDN licenses on evaluation machines. I use retail and OEM licenses on the systems I use for daily work. I allowed my Action Pack subscription to expire last year.
I have a copy of office ’07 Home and Student but am unable to install it to my PC. I have already installed it on my laptop. Shouldn’t I be able to install it to another device. How do I do that?
i want to download ms office 2007 on my pc