deepakumar,
I'll let you on a little tidbit of info.
The majority of us answering questions here--run, maybe once a month, maybe once a quarter, maybe only once but we run MalwareBytes.
Then we use for our virus/spyware/malware protection the best there is which is also free, namely, Microsoft Security Essentials.
Here's the draconian approach I use to clean up computer. This approach has never failed me.
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ANTI-VIRUS - VIRUS and MALWARE REMOVAL / PROTECTION
1. Download MalwareBytes. Malwarebytes
Malwarebytes
2. Disconnect from the Internet.
3. Disable your present antivirus software and firewall.
4. Remove your present antivirus software and firewall.
5. Install and run the MalwareBytes Quick Scan (remove any bad guys). 3min 29secs on my laptop.
6. Reconnect to Internet.
7. Update MalwareBytes.
8. Run malwarebytes quick scan again.(remove any bad guys). 3min 38secs on my laptop.
9. Run MalwareBytes full scan. 16min 8secs on my laptop. With large,full disk ~2hours.
A. Disable your present antivirus software and firewall
B. Remove your present antivirus software
C. Download Microsoft Security Essentials.
http://www.microsoft.com/security_essentials/
D. Run Microsoft Security Essentials. Quick Scan - ~8 min on my laptop.
E. Run Microsoft Security Essentials. Full Scan - ~ 1hr 50 min on my laptop.
Now I advise you to uninstall MalwareBytes and only install again when and if you need it.
Why?, you ask. Leaving MalwareBytes installed slowed my system. AutoRuns showed MalwareBytes processes running even after exiting from MalwareBytes.
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