Is it possible using GuiXT to link something on the screen to an MS Word document (i.e. a .doc file)?

Yes, this is possible. There are several options. Options
2-4 use our "Controls" and/or "InputAssistant components:

Option 1
Use a small Image (Icon) where you point to the .doc file with the
start="..." option. The file name can contain variables:

Image (...,...) "viewdoc.gif" start="docs\xxx&[Account].doc"

Option 2
Create a pushbutton "View document" that starts an InputScript. In the
InputScript, use

Start "docs\xxx&[Account].doc"

Option 3
Save the .doc file as .rtf file and integrate the document view into the

Control (x1,y1) (x2,y2)  progid="rtf\xxx&[Account].rtf"  name="mydoc"