Yea, it looks like your problems may lie in your proxy software. Check in your proxy software setup to see if you are blocking HTTP for any reason - check to ensure that there is not some HTTP proxy service running that may be blocking all of your HTTP. If you can't find anything within the setup of your proxy software, completly uninstall it and then just as a check, make sure you can receive HTTP. Then, since you still need to protect your machine, consider installing a software firewall such as Zone Alarm if you are not running a LAN. If you are running a LAN, you may want to look into another proxy software package.

Hope this helps...