How to bypass the message "There is a pending reboot for this product" when trying to re-install Intel RST
Solution 1:
After a lot of frustrating time wasted on Google, I thought about using Sysinternal's Process Monitor. It is a handy tool for spying on various things a process does under the hood, and one of these things is which registry keys it tries to access.
Using this tool, I discovered that the IRST installer was accessing the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intel\Setup$
All I had to do to solve the problem was delete this key, and I was on my way.