> I tried changing Windows font size in control panel, did not help.

Try setting the font pitch to 96 pixtels in the display setup.  This means going to the display setup in control panel and selecting "Normal" for the font size.

I still have extremely small font size in my To, Subject, and CC fields only, and I can not change this. To small to read.

 Message size text is not effected.

I use Vista Home Premium.

I tried changing Windows font size in control panel, did not help.

 I use Pegasus 4.51