upgrade of pro AV to I'net Security

Big problems with this upgrade, resulting in system freeze, unlocked by switching off. But reboot resulted in W XP Pro loading and shutting down soon after login screen. Only way out was using Safe Mode and then rebooting to Last good configuration. Initially, Avast reported software was activated immediately after installation. But Firewall was not activated and I used email activation code to instal new licence which avast confirmed. But under Protection in User Interface, initially a smiley appears replaced by unsmiley and message, Firewall is a paid feature and doesn’t come with Avast Internet Security !!! I need to have this firewall in place so what is the solution ?

The firewall is included in avast premier and IS.

Perform a repair of avast and see if the problem is solved.
If not, perform a clean installation of avast.

Sorry for delay but big issues with this. Using Avast clear in safe mode after repair resulted in same symptoms ie PC restarts soon after login screen appears or also if I have logged in to windows resulting in desktop appearing. Sometimes, system just freezes and only way out is to power down. System is XP Pro SP3 and no problems with Pro Antivirus. After 3 attempts to repair/clear/reinstal, gave up and downloaded Avast free with no problems. This auto restart after login screen suggests incompatibility with XP and performing chkdsk on boot up shows no problems. CCleaner also shows insignificant issues in registry clean. Sometimes message, “Embarrassed, AvastUI did not start” but trying to restart service from link fails. I am using I’net security on separate win 7/win 10 dual boot system with no problems. Win 10 updated to latest program with no issues but have delayed updating win 7 until this issue is resolved. Many thanks for your suggestion, I had forgotten about Avast Repair from control panel/uninstal programs

Can anyone help on this please ?

Is there any other security (related) software installed ? (or was there)
What happens if you perform a clean (custom) installation of avast with just the mail-/file- and webshield ?

Many thanks for coming back on this eddy. Only other related software is ZoneAlarm Free which has always been compatible with Avast software including Internet Security. I will try your suggestion but note that Avast free installed all components without any issue. I have taken this issue up with Support so expect they will need logs etc in due course which should provide the answer. Again thanks for your suggestion.