y'know ... let's try roping in a bit of additional help with this one. you're actually about the only 1607 i've seen in ages that hasn't responded to the standard three sets of advice (and the Tips and Pointers). the Hosts and the Engineers might be interested to see if there's anything out there slipping through the net of the standard advice.
let's try getting a installer log to the Discussions Hosts, so they can throw it over the fence so an Apple engineer can have a look at it.
Start menu -> Run... In the text field of the dialog that comes up, type in "cmd" and hit return.
In the command prompt dialog that comes up, find the iTunes installer on your desktop and drag it to this window. Then on the same line type in a space and then the following:
/Verbose"c:\log.txt" /V"ENABLE_QTLOGGING=TRUE"
There is no space between the e in Verbose and the double quote ("). There is no space between the V"Enable...
Hit return.
The installer will create two log files:
C:\log.txt and C:\qt.log
Find those files and
send them to a Discussions Host Put the URL to this discussion thread into the email, so that whoever gets it has some context. Let them know the version of itunes you’re trying to install, too … in general, give as much info as you can.
love, b