I had the same experience with mine.  I was using it one day and it was fine.  I was searching for more info about using the unit and came across a page that said the software could be updated.  It seemed like a good idea at the time, so I went through the steps to update it.  The result was the same as yours.  Basically a blank screen with a bunch of squiggly lines.  I can still use the buttons to navigate the pages, but it doesn't do any good since I can't read anything on it.  When I contacted Autel for support, their recommendation was to update it.  Just for kicks I tried it again but nothing has improved.  I've contacted Autel's customer service again but so far their only suggestion was to take it back to the retailer to get it fixed.  Yeah, sure, I'll take a $35 device to Wal-Mart and have them fix it.