You could try with a different email address as it is almost instantaneous that the email is sent. Does your ISP use a spam filter ?
Try the SSL Registration Page:
https://secure.avast.com/scripts/register.php?lang=ENG, choose the third option, "I'm a registered user and my key has expired and I need a new one," or words to that effect.
The auto update for the VPS Update is incremental and is measured in KBs rather than MBs so it shouldn't take long, or use much CPU % <30% If you don't have much RAM (what is your CPU and RAM ?) that may have an impact, but it shouldn't take very long.
Program updates are set to Ask as they are obviously going to be much larger, so you wouldn't want that set to auto, you could change the VPS Updates to Ask. Personally I don't believe this is required, as if yours is taking a long time there is something else wrong.