I installed Avast Internet Security 2014, the two machines its running ok on are both Windows 7 x64 and the one it wont work on is Windows XP x 32.
I was last using a trial version of Bit Defender, I used their removal tool to get rid of that, I even restored my comp to an earlier date, but all to no avail.
Having read the issues on this forum and elsewhere it looks like there is a compatability issue between this software and Windows XP, I do not understand how Avast do not highlight this when you are purchasing their product, or how they have not tried to resolve the issue, which appears to be ongoing since they released this version ?