I think Bob3160 is saying, can you try Chrome in ‘safe mode’ (safe mode for the browser) or equivalent? (Not safe mode for Windows). What happens? Safe mode for the browser will temporarily disable all your extensions, after which you can re-enable one at a time, restart the browser, to find the possible culprit.
Unfortunately Chrome doesn’t have a Safe Mode like Firefox. There are line commands but not something to fool with for the average user.
To turn off each extension you have installed for testing purposes and then turn them back on after your test is completed.
http://my.jetscreenshot.com/2701/m_20120814-59vd-54kb.jpg
on one of these PCs i uninstalled avast, installed avg, and when avg is active chrome does not work (again). so this does appear to not be an avast issue. it’s chrome or something else effecting chrome. the search continues for root cause and resolution, but that is likely not pertinent to this forum anymore. thank you.