My problem was when I wanted to switch between Dolby surround and DTX for movies, the software always crashed / lockup windows and I had to hard reboot, then remove the usb driver and logitech software then reinstall it all - very painful!
I also having problems with the logitech software itself (still use for my mouse), the last windows update left my monitor not working with power management / sleep modes when it is running, so I have to disable it from starting up with windows and all is well (very odd problem!) and now only run it when I want to change the mouse settings.
I believe you can resolve the problem similarly, try removing all the software and drivers for both the realtek and logitech, then reinstall the batch, that may work to resolve your sound problems (at least until the next windows update!)
When I switched to the SB Play!3 I now do not have any sound problems at all after windows updates, well worth the investment IMO seems like Sound Blaster has good software and drivers and unfortunately cannot say the same about Realtek and Logitech
If you go with either the G1 usb or the AE-5 pci-e, that should resolve the issues as Sound Blaster software / drivers seem very stable. No experience with the AE-5 but I have used the G1 on other folks pc with gaming headsets and they are very satisfied as well, and you will never have to switch back to the realtek on-board sound in windows