Thanks neerman for your information.

I have some mail viruses on my computer. Sometimes it automatically sends emails to all my contacts. Some Chinese letters would be there on the email and some zip files or cab files will be there in the email.

Does any one know how to deal with this sort of viruses?

Basically I had this problem couple of times before and I got some other spywares(fake windows security alert) were also in my computer. So I tried Trend Micro's House Call, Kasperspy Internet Security, Spybot Search and Destroy, and one Semantics Virtumode remover or something. This stopped that email Virus but could not delete the spyware at all.

So I have to restore my computer to the factory condition.

Then I had the fresh OS and everything fresh. So I installed the AVG free version. But on the same day the email virus appeared and it sent email automatically to all my contacts before. So I scanned my Computer with AVG, it told me I had these viruses and again I disinfected the virus. But after couple of hours again same virus problem happened in my mail.

Then I installed Spybot Search and Destroy and destroyed all the viruses and installed Commodo Firewall also. Now I am not getting those email virus problem. But I am not much sure I completely removed that mass mailer Virus or not. So have anybody faced any problem like this and solved it completely?