Windows: Which program can track the reg updates at software install and make a reg?

windows xp...
thanks

For the first part of your question, you need this, RegMon:
http://technet.microsoft.com/en-us/s.../bb896652.aspx
You can use any text editor to write .reg files.

SImplest way is to export entire registry before installation, export entire registry after installation and compare results with diff.

Regmon tracks access to the registry (which program tries to access what keys), it is good tool to find out which keys program are trying to access and with which API functions. But (AFAIK) it isn't good for detecting registry changes after installation - you'll have to dig through HUGE log file to find out what happened. Anyway, registry tracking is a popular subject in windows world, and I believe there is a good number of freeware/shareware programs to detect installation changes. I think OP should do google search on that.

Yeah, you're right, ErV. RegMon was the first thing that popped into my mind.

spybot - search and destroy has a registry tracker that can annoyingly pop up when ever something changes the registry... you would be amazed at how often this happens.

I wouldn't. Registry access can happen as fast as dozen times per second, depending on your software.