Hi the risk would be that the software would install partially only, minus the anti-virus, so best not to proceed until you've got rid of the AVG product.
Try running the AVG Removal Tool : http://www.avg.com/ww-en/utilities
It will be the first or second one depending on whether your machine is 32 or 64 bit.
Hi Mate Thanks for the advice -worked a dream. Problem solved with the AVG Removal Tool- much appreciated. Thanks again -Regards John W
Glad to help, all the best ;-)