Recently my Symantec Antivirus 2005 edition support contract ran out and I began to get the nagging, "fear of god" messages from the program telling me that my computer wasn't protected and that I could no longer get the latest virus definition updates.  It was very scary.  Ok, scary may not be the right word.  Annoying may be a better word.

Avast! Home Edition - http://www.avast.com/eng/avast_4_home.html
I started by installing and trying this free antivirus software product.  Early on, I ran into conflicts.  Avast! reported  that it could not properly initialize all of its scanning services while Symantec was installed.  My contract had run out, and I was using the older 2005 edition of Symantec anyway, so I uninstalled it so I could get a clean taste of what Avast! could do for me.

The biggest problem with the free version of Avast! is that you cannot schedule the virus scans to occur on a regular basis automatically.  You must manually run the scan yourself.  Overall, the software seemed pretty decent, easy to use, etc. however, for me, I want my computer to do things for me, not the other way around, so having to manually run scans was a bit of a deal breaker.  Of course, I could always upgrade to the paid version of Avast!, but my intention was to see what you could get for free.

AVG Antivirus Free Edition - http://free.grisoft.com/
I am currently trying this product, after having uninstalled Avast!.  From my point of view, there isn't much difference between AVG and Avast!.  They both appear to be competent in the function they perform.  AVG is generally user friendly, as was Avast!.  The big limitation with Avast! is not present with AVG and I am able to schedule a scan, however, only one scheduled task is permitted, and that task is limited in its defintion.  It only provides for a daily scheduled scan and you can only define the time at which it runs.

The most annoying thing I've found about AVG is that updates to virus definitions seem to always require a reboot of the computer.  The scheduled task for updates is similar to that of scans... only one is permitted and it is daily, or a manual process.  Neither of these options is perfect because you have to choose between manually updating the virus software yourself, or be faced with possibly having to reboot the computer on a daily basis in order to finish installing the update.  This annoyance is heighted by the fact that after an update is downloaded and installed, the AVG virus scanner is deactivated until you do reboot, which means delaying the reboot leaves you unprotected.

I am going to leave it another day or so, to see if the updates and reboots are truly a daily event, or if I've been unlucky with a steady stream of updates these last couple days.

So I left it a few more days, here are some of the results... the following list is "number of days between reboots" where 1 is the next day.  This assumes the software updates itself on a nightly basis, so this table provides a glimpse of just how often a reboot is required.

2 > reboot > 2 > reboot > 2 > reboot > 4 > reboot > 2 > reboot > 2 > reboot > 0 > reboot > 4 > reboot > 2

As you can see, AVG has me rebooting my machine almost every other day.  It is unfortunate that their update process involves a reboot so frequently.  It might be time to try out another offering...

I'll let you know what I find.

Update:
Ok, another oddity I've discovered with AVG.  It detected a virus on my machine, in an old archive file, so I'm not too concerned about it.  But here is the thing, it didn't notify me that it found a virus.  I had to go into the Test History (double checking to make sure they were still running) and that is when I saw that it found a virus.  In fact, it has been finding this virus with each scan every day for over a week.  If I hadn't gone into the Test History on my own, I still wouldn't have known about it.  Wierd. 

Update (2008-04-09):
I recently came across this site which provides the results of some comparison tests of many different antivirus products.  Worth a look if you are shopping around.
http://www.av-comparatives.org/

Update (2008-09-30):
Ok, well, time has passed.  I am still using AVG.  The latest version (8.0) seems to have fixed the frequent reboot issues that their update process used to cause, which is nice.  I don't notice it running now, which is a good thing... you want it doing the job, but you don't want it annoying you while it does it.