I was searching a lot through Qt forums and Google for the last few days, but I could not find any obvious answer to this question.
I found the -prefix
opti
IIRC on Windows, you have to do a sandbox install, you can't do the UNIX-typical "make install".
There are two options usually for building Qt, -prefix-install and -prefix /foo
You pick one, so if -prefix doesn't allow you to type make install, then I guess on Windows you have to use the -prefix-install route, which is a sandboxed install to the directory you extract Qt to.
I'm guessing you didn't try make install? So try that. It should install Qt to a separate directory away from the sources.