Yup, I don't think I would invest any more money into a Symantec Antivirus, Antispyware or Internet Security suites. I've used both Symantec's home version of antivirus software (Norton AV) plus I've used their enterprise software (Symantec Antivirus Server & Client) and have never been impressed with the level of protection they provide considering the performance hit a pc experiences during the use of those products. I've personally seen computers using Norton Internet Security that are overrun with all manner of virus/spyware/malware. If my friends purchase pc's that come bundled with Norton or McAfee security software (antivirus/spyware/firewall, etc.), the first thing I do is uninstall all of that bloatware. The only norton app I've used with success is Norton Utilities which comes with a decent app for scanning & repairing the windows registry. For an antivirus solution go with Grisoft's free or pro version of software, both are great to use. Grisoft now offers an anti-spyware and a rootkit removal solution as well (free & paid), adaware, spybot would also be in my toolkit for removing spyware as well as webroot's spysweeper. Microsoft's Defender is also good and it's free - but I wouldn't use defender as a stand-alone solution, you definitely have to use a few different apps for tackling this problem. Unhackme is also a must have for determining what's running on your pc. Running a good windows registry scan & repair utility like Tune up Utilities or JV Power Tools keeps your pc running smoothly & reliably. I don't have experience with Avast's antivirus software so I can't comment on it.

You should also be scanning your pc in windows safe mode, to catch the stuff you won't normally be able to remove when running windows in regular mode. Also a utility for removing the garbage files that accumulate over time is a must have, I've been using Clean Up v4.5.2 with great success lately although I hear CCleaner does a good job of that as well. Scanning your pc in safe mode for viruses & malware/spyware several times, rebooting in between each successful scan & removal of malware occurrences does the trick.

Also it goes without saying that if you run your pc using an adminstrator level account vs. a restricted user level account, you make it easier for this nasty stuff to accumulate on your pc.
If you run your pc in restricted mode for regular use and only run in admin mode to install software, perform updates & maintenance, your pc will likely experience very little or no malware infestation. Make sure you download & install the latest & greatest security & critical updates from the m$ update site, they're always patching some security issues on the current windows os and keeping your pc up to date is part of the process of keeping it safe.

Unfortunately it does seem that the regular home pc user with little pc experience requires an IT dept to keep their pc running reliably nowadays.

I've used a few. I have yet to find one that actually catches everything, but I have definitely had the best overall experience with Avast.

IMHO, Norton has become the Yahoo of anti-virus programs. It dumps all this crap in your PC that is almost impossible to get rid of and is riding on the success of how good it used to be.

I've had the opposite experience. I was using Avast and got a virus that Norton Internet security caught.

Since installing NIS (about three years now), I've never had any virus/malware issues.

No AV product is 100% effective, and there is always a chance that you will get a virus that Avast misses.

Well after 7 years I would hope it could find a virus - besides itself.