I did it using
VB.Net but saved them as .rtf files (Word), not .txt files (Notepad).
Create a Savefile Dilaog (name it sfd1) and double click it, then write this:
'This will make it save the file in Richtextbox1 as an RTF.
Richtextbox1.Savefile (sfd1.FileName)
Hope this helps!