Guitar Hero III for PC not playing nicely with power saving on Vista

I recently purchased Guitar Hero III for PC and while the game itself is fun and runs fine, the software in general is not very respectful to my settings.

My biggest gripe is that it seemingly disables monitor sleep mode. I have my monitor sleep after five minutes and I can see the importance of disabling that for the duration of the game, but after I exit my monitor doesn't sleep anymore, what's worse is that even after reboots it still doesn't sleep. I checked the power management control panel and all my settings are intact, so GH3 is doing something more sneaky.

A lesser, superficial gripe is that it disables cursor shadows after every exit, but at least I can fix that myself.

To add insult to injury, GH3 complains that its "security software" cannot load and the game terminates if I try to run Sysinternals Process Monitor to see what it's sticking its hands into.

To get back to the primary concern though, does anyone know what the game could be doing to break my power saving settings like this and if there's a way to fix it?

Thanks!