Hi Sushan,
I had faced the same issue of the elements in the setup window getting scaled. This resulted in some elements being inaccessible.
Resetting the 'scale' factor to 100% in the Windows display settings resolved the issue for me, and the setup window returned to its appropriate size. I also noticed that setting the 'text size' option in the Windows display settings to more than 100% caused similar problems.
Before and after screenshots:
Hope it helps.