I'm typing this on XP. For Windows 7, I have a full, retail purchased, on DVD copy of Windows 7 Professional. Okay, but so what? To install Windows 7:
(1) Find a boot partition -- actually I do have one available.
(2) Wonder if Windows 7 will run on my hardware with a 32 bit processor and a 1.8 GHz clock. E.g., I've not seen a statement from Microsoft on what hardware Windows 7 needs.
(3) Especially wonder what of my crucial old software will run on Windows 7. E.g., I don't want to get into the 'security mud wrestling' of Vista.
(4) What's new in Windows 7 I will have to waste time learning?
(5) What is in XP that I am using that will not be in Windows 7?
(6) What of my hardware, e.g., a FAX modem, Windows 7 won't work with?
(7) What if anything I could want will I get from Windows 7 I don't have with XP? I haven't seen any such list from Microsoft.
(8) As far as I can tell, the main reason to install Windows 7 is just so that bug fixes will continue to be available. This matter of bugs is getting too convenient for Microsoft's bottom line.
(9) What about major software such as SQL Server I am running now on XP? Installing SQL Server was massively wasteful mud wrestling on XP, and I fear loss of some days of time getting SQL Server running and, then, loss of some weeks of time, literally, getting the system running again after the installation of SQL Server ruins my system requiring me to format a boot partition back to empty, reinstall XP from the DVD, install XP updates, no longer available?, that is, maybe the 'updates' I have still just pull the actual updates from Microsoft. Yes, SQL Server installation was bad enough it wiped out my favorite boot partition for XP and all the software I'd installed on it. My experience is that installing SQL Server is a big threat to all other software on the system.
The issues are not just buying Windows 7, guys; I've already done that, and the copy is sitting unopened on a bookshelf.
Microsoft: Document your products. Tell me what I need to know. Be clear. I've already bought your product and, still, due to lack of enough documentation am scared stiff to use it; I fear a disaster to my work. Did I mention you need to document your products, tell me what I need to know, and, by the way, document your products and tell me what I need to know? Did I mention those things?