Try This:
On your Microsoft Word, under tool menu, then record macro... then open any .doc file, then print... under tool menu again stop recording.... then try openning the macro you have recorded, then you can see how vba code for Microsoft word in openning and printing...
In VB.Net, ('i've never tried this vb.net, but in previous vb, i've done a quite sometimes but not with Microsoft word, perhaps in Microsft Excel.) Add the .dll or .tlb (not sure!) Microsoft Word into your reference. then Create Object for word, then etc., etc....
I'm not sure about this, just try it...