Running multiple security solutions of the same type on a single machine is not recommended, and by personal experience a lot of combos don't go along well. Yet I've used Symantec AV Corp/Endpoint Protection with NOD32 without issues for years. For some months now, I've moded to COMODO AV + firewall and Avira. I tested the combo for months and it seems stable now. As of yesterday Microsoft released their Windows Security Essentials on Windows Update, free to download for anyone. Thus, my current security setup looks like this.

I only use Comodo, Ad-aware free, and Avast. Plus built-in windows security. Except defender, I hate that thing.

By stable do you mean, if you get a virus, you wont get the blue screen of death?

Because my bro told me he wanted to find out what would happen if two anti-virus software went after the same virus. So he did just that, got two anti-virus software and programmed a tiny virus. The end result was the school had to reset their system due to blue screen of death.

They don't go after it together. In my case COMODO always takes priority. When it finds an suspect file, it pops the usual query message, and only AFTER I've chosen to allow it, Avira will also ask.

Anti-attack software is for people who are afraid of the internet.

The only security program I ever used in conjunction with another was CA, which I used alongside CA-AA1, which is the pi--- Erm... The uh, non-commercially available, yet easily obtainable version...

And the only reason I ever used CA was to gain EXP for using hexa- and c//-write to eliminate infections.

Anti-attack software is useless.

I agree ^

However i will say the one protection i do use is spybot S&D but only the passive protection. aka: cookie blocking and host file.

"fast" pc with nothing VS "slow" pc with anti-virus
^winner^

That was as many as six years ago. I haven't run an anti-anything on Behemoth since I first booted her up with 2.6.2 in full Handwrite.