Check whether a s/w creates registry entry?

I'm installing a new software on my PC. I want to trace whether it
is making any entry in registry or creating any new key in registry. How can i check it? Because it is not necessary that it is making entry with its own name. It can make entry with any name. So how to trace it? Any clue? Please help..

Active Registry Monitor does this.
Costs i think?

Else what you could do is make a backup of the registry, install the software, restore the backed up version then run the software if it doesnt work then it made a registry change.

b :)