I work in IT and my computer is fine, it's definitely a bug, it's not because it work on some set-up that there is no bug in a software
I see in your screenshot that you are not using aero theme, is there any reason ?
Because I don't like it and use 4 monitors so I keep everything fluid and barebone.
why there are icons on the left of the classic title bar icons (reduce, maximize and close buttons) ?
Because I use 4 monitors and need to manage it efficiently when I program so I use Active Window Manager
since many years.
reinstall windows 7 sp1 with an unmodifed ISO.
Your assumption is false, my Windows 7 pro 64 (SP1) is not modified in any way, it was installed with the retail ISO Win7/64/SP1
I don't say and never said "winreducer" did not work on other setup than mine, I just say that on mine it did not work and it's the only software that don't work, after testing the .net framework we know also that .net is not the problem.
Here's the log of Process Monitor
if you want to look at: https://dl.dropboxusercontent.com/s/bb7ownu3x3hnbp5/LogfileWinReducer.zip
You need ProcMon to see it correctly: https://technet.microsoft.com/en-us/sysinternals/processmonitor.aspx