I had a very similar problem, brought upon by an ill-intended ActiveX control embedded in a web page, which inserted two dialer executable files on my PC's hard drive, changing my default broadband connection password and phone number.
AVG Anti-Virus didn't detect the files, nor both Ad-Aware and Spybot Search & Destroy. However, another tool was successful at finding and removing these dialers: Emsi Software's a-squared. There is a free version available for download and although it supports malware scanning and removing only (no configuration features at all, for example) this should be all you need. Just Google up the name of the program and give it a try.
Without making major changes, you need an AV to remove a virus. There are several free ones like Avast!. If you really need to avoid an AV you can reinstall windows or install Linux.
not the newer ones
Download an anti-virus utility! Windows Defender and Counterspy are ones that have worked for me.
A Trojan Horse is not a specific virus; rather, it is a name for several more violent viruses. Most Trojan horses are detectable, depending on which Anti-Virus software you use, however new ones are created daily, and it's impossible for anyone to keep up.
Yeah, the new ones.
Most of the phone carriers who offer wireless broadband offer special rates for buisness and companies looking for service for multiple people. Please check with ones in your area for more details.
There are some free anti virus software available but it is not as good as the paid ones. If the virus is preventing you from being able to use your virus software you will have to go into safe mode and remove the virus manually.
Broadband services vary widely across the country. You can start by looking up the yellow pages to see which are the better know companies in your part of the country. After some research you should have a better idea which are the better ones.
You can only do the deleted manually if you know the exact name of the virus . You know the virus has not morphed. You also know the exact entries in the registry you need to delete. (if you delete the wrong ones your system would shut down.
Anti-virus programs don't 'lie' as such - but they cannot find EVERY virus, as new ones are being written daily. An anti-virus program is only as good as its virus database.
how does each stimilus changes ones behaviour
Bacteria cells. They are the smallest living thing on Earth (known to man).