There are some strange repercussions happening when system restore is used, there have been a few cases like this.
Is there any reason why you are still using 4.8 when 5.0 has been out for almost 4 months ?
Download the latest version of avast 4.8 http://www.avast.com/free-antivirus-download#tab4 and save it to your HDD, somewhere you can find it again (if you didn’t save it previously). Use that when you reinstall. Ensure that you scroll down and select the avast direct download link for the English version and not Cnet as that is for an on-line installation (not what you want to do).
Download the avast! Uninstall Utility, find it here ensure you get the version5 one, aswClear5.exe and save it to your HDD.
Now uninstall (using add remove programs, if you can’t do that start from the next step), reboot.- 2. run the avast! Uninstall Utility from safe mode, once complete reboot into normal mode.- 3. install the latest version, reboot.
The reason I use Avast! 4.8 Pro is a cost problem as I am retired and living on very limited income and still have about a year on the subscription order.