I wonder if it's just not an issue of how Windows 7 refuses to let you do some things in certain directories even though you're logged in on a full admin account and just denies you access? I hate upgrading my OS but I'll probably jump at the chance to get Windows 10 for free hoping that constant headache is improved.
What I do to get around those problems is to use
Unlocker to make sure no program really does have a directory or parent directory locked. And I've added the
Take Ownership entry to Explorer so all I have to do is right click, select Take Owership, and it fixes the problem most of the time.
On a few rare occasions I've had to boot into safe mode to install a program, but after that they've worked. However both NOOK for PC and NOOK Study installed without any hassles for me. There might be some conflict with another program, Windows updates (I've got all updates installed), I'd also try shutting off my AV program for the installation, and then add it to the exclusion list for the AV program.