You may want to search for a new version of the video driver for your specific system.
According to your first post, both BSOD happened while you were using a web browser application (you don't say if both times you were using the same web browser).
So an additional possibility is for you to uninstall add-ons / plug-ins, uninstall your browser, then reboot and install the latest version of those programs/tools. Then reboot again. (This is in addition to an update of your video driver, if it is available).
Of course I can't assure you that no BSOD will happen again, but those are all the common items involved in your description (besides your hardware).