Andreas,
I'm pretty new to vb.net also, but I tried to check this out for you.
The first thing I did was use "intillisense" in a code window by typing
"inputbox", then a period (.). This displays all the parameters the
inputbox functions takes. "Font" isn't one of them, nor is anything
else (such as "style") that might cover fonts.
Then I pressed F1 with the cursor resting on "inputbox" in my code, to
bring up Help regarding InputBox. I think based on the Help I got that
the InputBox function seems to be a "member" of the messagebox class of
the System.Windows.Forms namespace. I didn't see any property or method
right away that might include controlling fonts, but you might look
around in that namespace for something. To do that, get in a code
window, or the "immediate" window, and type "System.Widows.Forms" and
then a dot (.) to bring up a list of all the members of that namespace.
From what I can see, I don't think you are going to find a way to
control the font in InputBox or MsgBox or MessageBox using vb.net.
However, why don't you just create
a regular form to duplicate the InputBox features. (This is also beyond
me, but you might look into creating your own Class, and base it in
part on the MessageBox class, and add font capabilities to your Class.)
Sorry I couldn't do more. Hopefully an expert vb programmer will see
your question and try to help you.
Good Luck!