Very strange... I went to the "About" section in Avast 5 and it told me that the program version was unknown, the Virus definitions version was also listed as unknown´, I clicked on update but a message came up informing me that updating was not possible as the program was disabled.
Reckoning on un-installing Avast using Revo uninstaller, I went to the Win 7 task manager and tried to stop Avast as it showed that it WAS STILL running.... stopping the process was refused !
I then decided to restore the system to yesterday before trying to do the uninstall. On rebooting, system restore informed me that the restore wasn't done able to be done due to an open antivirus program file and would revert to the state that it was before attempting the restore. However when the desktop appeared Avast 5 was running properly again with all shields activated, very weird !
I am guessing that something fouled up when the update was appled, as the task bar pop up telling me that Avast had been updated did not disappear as it usually does, I had to click it off. It was after that, that I noticed the red cross on the icon.
Anyway I am happy again