I uninstalled AVG by system restore

Cyril, Try the AVG Remover (http://www.avg.com/tools#tba2).
AVG Guru

I uninstalled AVG by system restore but a large file is left in program files. Can I just delete it?

Cyril, Try the AVG Remover (http://www.avg.com/tools#tba2).
AVG Guru