This problem can be caused by the fact
that when installing some programs or drivers your Windows in
accessing the registry a lot of times. In this situation the real-time
monitoring feature of the Installation Monitor can slow down a lot the
computer (it might even look like the computer is
completely blocked).
In such situations I advice you to right-click on the "M" icon of the
Installation Monitor. Then choose Settings. Change the Monitoring type
to "Monitor registry by making snapshots". The monitoring will be a
little slower in the beginning but it might perform faster overall.
After finishing the installation of the program, you can switch back
to the "Live monitoring" option which usually performs a lot faster.
Also, please note that the "slow down problem" appears for almost any
monitoring program. Sorry...