Viruses and Spyware

Today I had to clean up a Windows system which crashed. Once I managed to start it up, surprise... lots of spyware was popping out with fake warnings of infections, messages that say that in order to remove the findings you should pay etc. So I started to hunt them down, remove startup applications from registry, etc. I managed also to uninstall some of them, but still big problems. Processes that were launching each other when killed... a total nightmare. So it was the time to bring up the power tools. I managed after several hours to get the Internet connection back up and running and I could download SpyBot Search and Destroy (from http://www.safer-networking.org/) and install it. The resident component started to pop out and after several clicks I've managed to leave it on "auto kill" while meanwhile I have launched a full scan. After the scan come the cleanup (a long list of spyware and adware). A reboot was in order and I scheduled another startup scan to clean up the remaining pests. Finally it was stabilised. Next step was to take an online virus scan (http://support.f-secure.com/enu/home/ols.shtml)... Surprise! Another 176 viruses!
That was pretty bad. But how did the system got in that mess? Well it is enough to get one pest and it will take care of downloading the rest... One mistake can mean a lot!
So what should you do?

• never click on windows that say that you are or you may be infected with whatever virus or spyware or adware or whatever
• use a good antivirus and keep it updated
• turn on the firewall
• use a browser protection tool such as SpyBot Search and Destroy or Lavasoft AdAware (http://www.lavasoftusa.com/software/adaware/)
• keep your system patched
• document and educate yourself about safe Internet navigation so you can reduce the risk of being accidentally infected

That are some of the things, if I missed some, please tell me...