I was using version 9.0.0.736 as a matter of fact (did a clean install the day it got released).
I also tried it's previous version, 9.0.0.4-something, same result.
9.0.0.463. I hope you weren't using it on Windows 7. It
appeared to be working, when in fact it wasn't. Kaspersky Labs itself warned not to use it on Windows 7.
I recently moved to Avira AntiVir Personal (KIS license expired), and I gotta say, I'm loving every minute of it.
Just give it a try. You'll notice that your system will become much 'snappier' as a result (not to mention that Avira has a better protection rate than KIS, so you'll be safer as well, plus, with it's new updating system in place, every update is like ~64kb... lolz).
I actually
did try Avira a few months ago, when I was playing with Windows 7 RC and Avira was one of the few compatible antivirus programs already available for it at the time. I don't remember what was wrong with it, but I uninstalled it for Avast! after a while. I didn't want to spend money just for testing an RC, so I only used free security programs. I am using the free version of Avast! now on the XP virtual machine I'm running under VMware on Windows 7.
Now, the "best" antivirus is not only a tricky subject, but one that runs the risk of starting a passionate flame war, like Linux vs. Windows vs. Mac. It gets complicated because if you see 10 different antivirus tests, you will see 10 wildly different rankings. There is clearly a top tier of products - Kaspersky, Avira, Avast!, McAfee, Symantec, BitDefender, NOD32 - and maybe a close second tier with AVG and Panda, for example, but within those tiers there is no consistent clear winner through all tests. They have no consistent rates of detection, and all will leave gaps that others will cover and vice versa. It has always been so, but there used to be just a minor variation with obscure and uncommon types of malware. Not any more.
The fact is that the question is trickier now than it has ever been. The whole security software market is in a crisis, because zero-day attacks are happening much faster than
any vendor can handle it. Attack and infection vectors and stealthing techniques are also getting more sophisticated than ever. In short,
all products are failing miserably and anyone who relies just on them to feel secure is deceiving oneself. Vendors are responding by tightening heuristics (leading to a lot of false alarms) and dumping threats with low incidence from their databases to make room for new ones (something they will be very reluctant to confess, but
all of them are doing it).
A year or two ago, I was a passionate Kaspersky fan and evangelist. And Kaspersky deserved my devotion and loyalty - at that time. Now it is just one more product. It certainly still is in the top tier, but it is not king any more like it used to be. Nor is any of its competitors.
I am still in an early phase of configuring and installing things in my new Windows 7 install, but I intend to tighten it with two or three further antiviruses. Yes, you
can use more than one without conflicts, provided you use only one
resident program at a time. Dedicated spyware detectors also usually don't conflict with antivirus programs - Spyware Doctor lived harmoniously with KIS in my old XP install. KIS was my main protection, but I also had BitDefender Free (which can only perform manual scans, but doesn't stay resident), Malwarebytes' Anti-Malware Free (ditto) and a-Squared Free (same, though it had a VERY high false positive rate and I didn't trust it). I often ran full system scans with them while I went to sleep or had to go out, to supplement Kaspersky's own detection. However, all of them give so many false positives these days that one has to use discretion and common sense to decide if a threat is real or not. As a former IT professional, that's easy for me, but not for most average users.
I also submit anything suspicious to Virustotal.com (and likewise, then I have to use the same discretion and common sense to decide whether the results of its 40-odd antivirus tests mean a real threat or not) and make use of on-line scans that most major vendors offer today, though in this case conflicts
may occur, since then I can't turn off Kaspersky as I could when doing an off-line scan (unplugging the PC from the Internet for the duration of the scan), and the scanning process is much slower as well. ESET's on-line NOD32 scan, in particular, is painfully slow, but it has detected hidden spyware more than once and more than any other. But I tested the antivirus program itself and it gives too many false alarms (including one in a 6-year-old ZIP file that only contained archived .TXT and .PDF files!) and the interface doesn't offer you any freedom to decide what to do next. I didn't like its usability.
However,
the single most effective preventive measure is your habits: not accepting suspicious attachments, configuring your e-mail client not to fetch remote images and not to run scripts, not visiting suspicious sites, etc. (though with so many XSS attacks these days even in unsuspecting reputable sites, you often do it without even knowing). The
second most effective one is keeping all your software up-to-date and patched, closing the door to known vulnerabilities - not only all the latest Windows Updates, but the latest versions of everything you use.
Secunia Personal Software Inspector is free for personal use and great for that.
CNET and
Filehippo.com also have more limited tools that detect if there is a newer version at least of the software they feature for download from their respective sites.
For Firewall I decided to go with PC Tools' Firewall Plus. Higher score than KIS on Matousec.com's most recent Proactive Security Challenge test. Rock Solid.
I will certainly be using Kaspersky Internet Security 2010 at least until late March, when my current license expires, because one can't say that it isn't adequate protection as far as it goes, and like I said, it is not significantly impairing performance here. However, unlike in previous years, I am not sure that this time I will blindly and thoughtlessly just renew my license. For starters, Kaspersky's user interface became very bad and confusing in KIS 2009, and got even worse in KIS 2010 - I'm always looking where I will find some function, and it may be at odd places (for example, application activity rule configuration is not on the "Settings" window but in an obscure tiny link in the main window!).
More importantly, being forced to use separate products for antivirus and firewall purposes rather than a monolithic security suite, when I was exploring Windows 7 RC and there were not many compatible products, reminded me how good it is to have that flexibility. For example, with a separate antivirus, I could turn it off while doing an on-line scan to avoid conflicts and speed up the process, without losing firewall protection. (Kaspersky does allow selective activation/deactivation of components, but it gets really nasty when you do it, popping scandalously scary alerts all the time - it's really annoying!)
True that a firewall these days is much more than just monitoring your network connections and allowing or denying traffic according to rules. I used PC Tools' Firewall on RC for lack of a better alternative at the time (actually, there was one: Comodo, but with all those reputation problems, questionable antics and bullying of discussion forums and Softpedia, it lost my trust), but it was only a conventional firewall and I missed other security features that KIS had, like application activity monitoring and sandboxed execution ("Safe Run"). I was using the free version and maybe the paid one has more features, but I found PC Tools too simplistic.
I'm not sure about the resident antivirus I will use. It may be Kaspersky Antivirus, Avira, as you suggested, or Avast!. BitDefender would also be a good choice, and Symantec/Norton has regained its reputation of being effective as in the old days, but they are way too heavy on the system. As for the firewall, I'm inclined to use either Online Armor or Agnitum Outpost. I'm using the free version of Online Armor on my XP virtual machine and I'm very impressed with it: simple, clear interface and very light, yet also very tight, including very strict application monitoring even in the free version.
Avira + PC Tools' Firewall + Malwarebytes FTW!!111!!
Although I can't say for sure that I would use the same combo (especially because of PC Tools), I also wouldn't say that you have made bad choices. It is certainly a very reasonable combination, to say the least.