Upon moving from Windows XP to Vista, a new PC, the Microsoft Mouse has
taken up a bad habit of double clicking when it is only clicked once.

This is really common with Microsoft mice. The problem is due to the
microswitch going "noisy".

If you're OK with a soldering iron you could swap it with the microswitch
under the right-click button - I've done this several times over the past
several years. The right mouse button is used far less often, and double
clicks on it rarely do any harm.

Alternatively, you might just want to buy a new mouse. Logitech mice seem
slightly less prone to it, although still not immune. Presumably they have
better 'debounce' built in.

SteveT