a) In case there are left-over start-up files, hold down the SHIFT and CONTROL keys as Mathematica starts up. This will reset any existing front-end startup files to default contents.
b) It might be worth removing Mathematica from the control panel and then searching the whole computer, including "Hidden files and folders" and deleting all directories named Mathematica. Then restart the computer and re-install.
c) If neither of these fixes the problem, please send the following diagnostic information to email@example.com.
- the output from evaluating
in MathKernel. (This is long. Copy and paste it into return
email or put it into a file and attach the file.)
- the output from running systeminfo in a command-prompt window
(via Start - Programs - Accessories, or Start - Run - cmd.exe)
(This also is long. Copy and paste it into return email or put it
into a file and attach the file.)
My apologies for the inconvenience.