Thanks for the reply. I’m not blaming AVAST necessarily, only stating that when I deleted it the problem went away. Now for some details:
Win 7 (64 bit)
Firewall: Zonealarm ver: 11.0.768
AVAST: Free version. Can’t tell you the version number, since I updated it today through the AVAST software, and had to delete it to post this.

AVAST has been my anti-virus software for a year (with no problems). I have no other security software.