Kill viruses on your own:

This is a simple tutorial on what has to be done when you know that your system is affected by a virus and you or your anti-virus can't do anything about it. This one would be very comfortable to users who have had their system for atleast more than 2 years. Even if you don't, little bit of knowledge on basic Startup programs is enough to get rid of any viruses that affect your system. No virus was ever created that can destroy any system completely. Alright, there may be some but lets not talk about them right now. Just simple viruses(or in other words, most of the viruses). I'm telling you this because most of the viruses that are created usually are not much damageable. And this is because when you're making a tough virus that affects your boot menu, Hard disk and such crucial hardware, you will need a lot of effort to be put. This, you wouldn't do unless something is wrong with your brain. 

                                         Now lets say my system is affected by a virus and I don't have an anti-virus to kill it. At these cases, I usually check the Task Manager and goto the Processes Tab. Here, I take a look at all the processes that are running in my system and end any process that I find as suspicious one. If you end any Windows processes by mistake, you don't really need to panic. All that might happen is that your system would restart in a minute.

                              The name of the process that I found suspicious is "servicas.exe". The main aim of the virus would be to make me believe that the process is "services.exe". This one is actually a Windows process without which the system may fail. But since I noticed the wrong spelling, I could guess and end the task that is run by that virus.

                               But I'm not done with it yet. I'll open the registry now( Start--> Run and type "regedit") and search for the item consisting of the name "servicas.exe". This can be done by pressing Ctrl+F while the registry is open. I'll definitely find one or more registry entries in it consisting that name. While editing the registry, it should always be backed up so that we can restore any settings later on if we messed up any. So I finally delete only the path of this virus in all the registry keys that I find without forgetting to save the address where the virus is residing.

                               Now that I know where the virus lives, I can delete it directly at the next boot-up. But most viruses drop files whose attributes don't allow you to delete them. This can be removed by using the Command Prompt. Just navigate to that path and type "attrib -r -a -s -h" and after that, "del virus_name". Now you've finally gotten rid of that virus.

                               Instead of the Task Manager, you can also go to the Start-->Run and type "Msconfig". A window would be displayed having several items. Navigate to the Startup Tab and uncheck the name of the virus or any program that you find as useless. You will also find the Sound driver and the video driver. So make sure you don't touch those. After you're done, reboot your system and follow the registry instructions that are given above.

Caution: The above tutorial can cause your system to completely crash. So don't implement it unless you know your computer and its programs very well. The instructions discussed above was implemented several hundreds of times and that is the reason why it was posted here. We would not be responsible if anything happens to your system.