How can you find the most recent entry in the registry?

"Not that I know of as there are thousands of operations happening all the time and I do not think that there is a copy of date/times of writes.

You may want to take a look at Microsoft/Sysinternals Process Monitor, you should be able to filter the included results to just registry writes.

Alternatively, you can export an offline copy of the registry and then do it again later and compare the two files using your favourite Diff type tool. I have seen a few programs specialised for Registry comparison, but I can't remember their names. If I remember, I will edit this answer."