Sounds like program corruption. You may have gotten a bad update - or perhaps you're on the beta release of Chrome. Windows version is irrelevant. And disk defrag fixes absolutely nothing; it just organizes the data on your hard drive so that it can access data quicker.
Try using another browser and see if you get the same problem. If a different browser works - such as Internet Explorer or Firefox - but you would like to use Chrome still, then uninstall Chrome and download the latest
stable release, and install that.
*If you uninstall Chrome, I recommend using Revo Uninstaller and using the "Advanced" feature during removal. Doing so will perform a clean uninstall and better clear out leftover files.
Let us know if that works for ya.