Thanks, everyone, for your input (no pun intended) on this.

Though nothing so far has revealed a perfect fix for devanagari in MS-Word, the
hint about the "f" led me to try the virama in the microsoft devanagari keyboard,
which is the "d". This worked perfectly. Thus, to type क्त्य, one just has to type k + d + l + d + /.
Easy enough, but perhaps not so intuitive. In any event, it does indeed seem possible to
type Sanskrit devanagari in Word without the conjuncts falling apart.

Matthew