Virus scanners - absolute rubbish?

[Wix]

I had a virus on my computer, it kept starting intenet explorer tasks on startup and it was taking up 95% of my memory. I scanned the computer with AVG. It found 3 files. I removed the 3 files and it made no difference. Everytime i tried to close the internet explorer task, another process opened, created a new internet explorer task and deleted itself. It was bloody annoying. I took note of the procresses and did some searches. I then searched for all the .exe files on my computer. That turned up 2 culprits and there was 1 file i was unsure of, so i left it.
Deleting those files made no difference. I downloded spybot search and destroy, and ran a scan. A few things turned up, i deleted them and that made no difference. I then looked at things starting up on stsrtup, i deleted 2 processess and there was that 1 i was unsure of again. That made no difference, then i thought, bloody hell its got to be that suspicious one doing it. I looked at the path and it looked malicious, i deleted the file and my computer was fine after that.
The point of this long story is, the virus scanner didn't work so i had to remove the virus myself. So whats the point of having the scanner?
btw: The software company that gave me the virus is i big trouble, i reported them to a internet protection group.

[Wix]

No fender, i didn't. I did think about safe mode but decided it wouldn't make any difference.

[198x]

It can vary from virii.

What you had was a start-up virus. Obviously when the computer starts up the virus kicks in and sends out files to folders. The scanner then picks up these files and deletes them but sometimes not the source. So when you restart your computer the source is still there and this process repeats itself.

I had this problem on my Win 98 PC ages ago, and I didn't even know it was happening until I checked msconfig.

[Ethel]

Viruses, not virii - which means 'man',

http://linuxmafia.com/~rick/faq/plural-of-viru s.html

[198x]

Viruses and Virii.

Viri means 'men' in Latin not Virii.

"the form virii remains popular in some Internet communities. There may be several reasons for the use of this word even when it is known to be unusual"

http://en.wikipedia.org/wiki/Plural_of_virus