Heggi,
Eddy's words are sound. If you like Avast on your own computer, let us help you get it working on the family computer in question.......especially on that one!
AVG is ok, but Avast is better.
Without the error message, it is hard to tell why Avast did not install, but I believe along the lines that Eddy mentioned. NAV is notorius as causing problems with new antivirus software unless it is removed
completely.In general, YES...Many users have had some installation problems with Avast, but they are different, but those with NAV will be much the same. It is not uncommon.
Please give Avast another try.