I have the exact same issue. In Chrome, when the CGPS extension is enabled (Settings > Extensions > XFINITY Constant Guard Protection Suite1.12.1012.1) then any forms will hang or be very slow. If I uncheck the CGPS extension Chrome works just fine. I don't see this with Firefox or IE, but my primary browser is Chrome.
Below is the response posted in another CGPS forum with regards to the Google Chrome browser crashing.
The issues with Chrome are ongoing, and are certainly not restricted to Constant Guard. When the Chrome session crashes, it will bring down whatever application was running when it crashed, and will list that application - it does not mean that Norton crashed Chrome, or Constant Guard crashed Chrome, or MSN crashed chrome. It means that something crashed Chrome and took that application with it.
We are hoping that the Chrome crashing issues subside with the release of Chrome 20. Due to the nature of my job, I run IE, Firefox, and Chrome with CGPS, and have seen several crashes with Chrome - but not enough to worry about - and that is dissimilar to some of the posts I've seen here, and to the ticketing which comes through our Support phones, chat, and webforms. It is still not "huge." Within the next few days we will release an update to Constant Guard Protection Suite to be released in conjunction with the next browser updates. We think that the combination of this release and the release of Chrome 20 will resolve the crashing you are seeing.
For right now - there isn't a solution other than to use IE or Firefox as the default browser, and use Chrome as your normal browser - just not set as the default. I do think this issue will be resolved between our release and the next Chrome release.
Just installed the new "Norton Security Suite" made available in 2015 from Comcast and experienced a drastic slowdown of Chrome. I solved the problem by uninstalling Chrome (in Windows 8.1 go to "Control Panel", select Programs and Features", select "Chrome" and click the "Uninstall" button; you have to complely exit Chrome first including the Notification feature in the System Tray). Then re-install Chrome by downloading and running ChromeSetup from Google. After doing this everything works swiftly again... all browsers (tried Chrome, Internet Explorer, and Firefox) are running great with Norton Security Suite installed.