Just an update. I was able to to install the newer version (7.14.10.1437) of the graphic driver by uninstalling the old and following the instructions for the workaround
http://www.intel.com/support/graphics/sb/CS-022355.htm,, and then i deleted all known instances (to recycle bin) of the offending Sigma file (6.10.5511.0 or earlier; mine was 6.10.0.5343), and stopped it from loading in the BIOS. I now have no audio. I also deleted any old versions of Intel Igdkmd32.sys –between and including driver 7.14.10.1322 and 7.14.10.1403 - leaving only version 7.14.10.1437. Still no go, as b4.
