Both issues result from interference from third-party applications. We have narrowed it down to Skype (at least), so shutting it down, before installing or playing the game, should fix this.
If it doesn't, please shut down all unnecessary applications, or perform a "clean boot" to create a bare-minimum user account, with the fewest applications running in the background.
To perform a clean boot on your system, please follow one of these guides:
Windows Vista, 7 and 8.