Hi.
Please consider this from Microsoft about your 0x74 error:
"Try restarting the computer by selecting "last known good configuration" in the boot options.If the restart does not fix the problem, the registry damage is too extensive. You must reinstall the OS or use the Emergency Repair Disk (ERD) that you previously created by using the Windows Backup tool."
You can press f8 continuosly at startup to get the boot choice screen.
With that being said and/or tried, you may attempt to remove Avira with the special tool found here by booting to safe mode + networking:
AV Uninstallers - Windows 7 Forums