Installing Adobe TCS 1.3

[Peter Hirons]

Apologies for the cross-posting, but I'm sure I've seen the answer to
this on one of these lists, but can't find it.

Running on Win XP Sp3.

I have a copy of TCS1.3 (I know it's old, but it's a long story) that
refuses to accept the serial number.  I currently have it running as a
30-day trial and the clock is ticking!  Adobe Support can't solve it and
only suggest uninstalling and re-installing.

I know I saw on one of these list a tip to delete a particular registry
entry.  Can anyone help?

Peter (a.k.a. Desperate of Clonakilty)