Windows 7 - Virus entered in my through website ... now my ms essentials do not update

please tell which antivirus i use ...???
how i remove virus....  

If you are having some what knowledge about Registry.
Then you make use of one Utility Program called "AutoRuns". I am using it. actually i am never using any Antivirus. Run it and delete some suspicious registry entry which used by the viruses. ( don't delete any entry if u r not sure. otherwise your windows can be corrupt )

http://technet.microsoft.com/en-us/sysinternals/bb963902.aspx

Restart and Simply Scan your computer from any antivirus. ( you can use AVG free antivirus ).