PC crashes during Windows 10 upgrade...

I have a i7 workstation with 24GB RAM and a one TB HDD.  It has the latest version of Norton 360 installed.  I tried to upgrade to Windows 10 and the computer keeps crashing.  It tries to repair itself repeatedly and keeps crashing with the same error irql_not_less_or_equal symevent64x86.sys... Finally, the Windows 10 installer reverted my computer back to its Windows 7 state but now some functions are broken.  Windows update no longer works.  Help!