|Use revo uninstaller to remove the AVG that partly installed or AVG has a removal tool, but you must get the right one for the version you are trying to uninstall. Clean out AVG, and try installing again. Did you have a virus and this is why you are trying to install anti-virus? Many viruses attack the anti virus programs, making re-installing difficult, in which case the system may need cleaned up before it will load a new anti virus properly. I personally for starters would remove AVG and any other old anti virus programs and then install AVAST, also free, and I prefer it to AVG. Here is a link to AVG's removal tools.|
Here is the link to revo uninstaller, the free version is all you need.
a link to avast.