Thanks Woolwell, but I've had the problem for a month or more and have been rather busy and never thought or had time to do anything about it earlier. Unfortunately I do not have a restore point to a time when Chrome was working fine.
I've also tried uninstalling by using Revo and choosing the advanced/most thorougher uninstall method to remove the remaining traces of Chrome, but it made no difference.
The firewall I run is one I've always ran (Vista's own firewall) and Avira anti virus, this I've ran for over 3 years.
I think I'll try loading my PC up in safe mode and see if I can run Chrome.