it seems that the solution given was only a short term fix. i had turned my computer off like i usually do and when i came back and turned it on to use it avast is having the same problem. are there any other solutions that i can try.
You could try a 'CLean Install':
Download the latest Avast version that you need and save then also download the aswclear.exe tool from here http://www.avast.com/uninstall-utility
and save, try to uninstall Avast normally first ( if unable to uninstall boot straight to safemode ) and when uninstalled reboot your system into safe mode ( tap f8 while starting the system ) and run the aswclear tool that you saved for all versions of Avast ever installed, when completed reboot back into normal mode and install the Avast copy you saved, reboot and add your license file.
Let us know if your issue is resolved.