If you turn off Explorer Replacement, then reboot, then insert a USB drive without any Opus windows ever opening, does the problem still happen then?
If so, it probably isn't related to Opus and Opus is just being taken out the same as the shell by whatever is crashing.
If there are crash dumps please zip and email them to us. They may let us tell you which component is crashing or possibly why.
Disabling antivirus, and disabling shell extensions using ShellExView, may also be worth a try in case they are involved. It's probably one or the other with a crash that happens as soon as a drive is inserted or opened. Crash, exit or high CPU usage when viewing certain directories has more.