Avast Internet Security - Wont start the firewall on 1/3 machines

[IrishPat2013]

I just purchased Avast Internet Security with a licence for 3 machines, it is working perfect on two of the machines (windows 7) but it will not activate the firewall on the third machine (windows XP)
Would appreciate any help that could resolve this please.

[Asyn]

Repair avast!:
1. Control Panel -> Add/Remove programs -> avast!
2. Click on 'Repair'.
3. Follow instructions.
4. Reboot.

[IrishPat2013]

Thanks for the suggestion, but I have tried all the usual tricks, uninstalled in safe mode, did the repair, but nothing seems to resolve the issue.....

[Asyn]

- Which version of IS..??
- OS..?? (32/64 Bit..? - which SP..?)
- Other security related software installed..??
- Which AV(s) did you use before avast!..??

[IrishPat2013]

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 ?

[Asyn]

...the one it wont work on is Windows XP x 32.

Which SP..??

[IrishPat2013]

The machine with the problem is running on Windows XP with Service Pack 3 installed...

[Asyn]

First, be sure to get rid of all remnants of your prior installed AVs.
-> http://www.avast.com/faq.php?article=AVKB11

Then:
1. Download avast! Internet Security: http://files.avast.com/iavs9x/avast_internet_security_setup.exe
2. Follow instructions: http://www.avast.com/uninstall-utility (Run this tool for all prior installed avast! versions..!!)
3. Reinstall avast! with the downloaded installer from point 1.
4. Reboot.

[IrishPat2013]

Well I am happy to say that at long last I have had a resolution to my problem, please see solution as advised by Avast Support below.
Hello,
This issue is caused by the Family Safety from Microsoft Security Essentials.


To solve this problem you need to uninstall Family Safety. If you can't find it on "Add or remove programs" you need first to download and install from Microsoft. Then uninstall Family Safety


Probably you also need to remove avast! with avastclear tool and make a clean install.