How to remove Adware.Multiplug/Variant?

Help! My new computer is infected by Adware.Multiplug/Variant. My Avast has detected and removed it, but Adware.Multiplug/Variant kept coming back when I scan my computer. Why can’t my anti-virus remove this nasty Worm? Should I remove this virus manually or change another anti-virus? Any help will appreciate.
Adware.Multiplug/Variant INTRODUCTION:

Adware.Multiplug/Variant is a malicious Worm that reduces security settings and drops files on the targeted computer. Adware.Multiplug/Variant is able to control the affected computer system without a user’s permission or knowledge. Adware.Multiplug/Variant can be surreptitiously installed on the compromised machine by other applications or any unsafe operations via security loopholes.

Adware.Multiplug/Variant can infect computers in various ways. For example, it can be downloaded via malicious drive-by-download scripts from corrupted porn and shareware / freeware websites, installed through spam email attachments, media downloads and social networks or executed by other threats on system.The Adware.Multiplug/Variant family disperse the spam emails which may be linked to the installers of the malware. You should take steps to get rid of Adware.Multiplug/Variant immediately before it creates more trouble.

INFECTED SYMPTOMS:
Adware.Multiplug/Variant degrades your computer performance
Adware.Multiplug/Variant infects your registry and uses it to launch annoying pop up ads out of nowhere. You can’t do anything just with the pops up.
Adware.Multiplug/Variant is a corrupt application
Adware.Multiplug/Variant may redirect you to tricky websites or point you to download malware programs
When you search something on online, Adware.Multiplug/Variant redirects you to malicious sites, displays annoying ads to you.

HOW TO REMOVE Adware.Multiplug/Variant QUICKLY?

Step1 : Install The World Fastest & Lightest PC Cleaner YAC.

Step2 : Once installed, open the program and click on the button “Examine now” in the Health Check item. YAC will now start to search for the malicious programs or files that may be installed on your computer.

Step3 : To remove the malicious programs or files that were detected in the previous step, please click on the Fix button. If there are plug-ins in your computer , YAC will now prompt you that “You need to close the browser to delete the plug-in, close now ?”.Please do so and then click on the Fix button .YAC will now delete all detected adware from your computer.

Tips : If your web browser homepage and search settings have been modfied by malicious toolbars, you can remove the programs with YAC and reset your web browser as follows:
•Choose the Protection item and set default browser, choose the browser you need.
•Then set homepage of the browser, click the button , choose the one you need.
•You can also set the search engine in this item. The lock setting will take effect after restarting the browser.
HOW TO REMOVE Adware.Multiplug/Variant MANUALLY?
In order to remove Adware.Multiplug/Variant manually you need to have technical knowledge first then only you can remove it manually as it requires the knowledge of system files and registry files and if you don’t have any idea about this then trying manual methods can lead you to more problematic situations and one wrong file deletion can make your system completely unusable. The Steps for manual Removal of Adware.Multiplug/Variant are:

Step 1:
•First of all restart your system in safe mode and for that press F8 key after you start you start your computer.
•Then select “Safe Mode With Networking” from the Advanced options window using down arrow key.

Step 2:
•Open task bar by pressing CTRL + DEL + ALT and terminate all the process related to Adware.Multiplug/Variant threat.

Step 3:
•Open Registry Window by typing “regedit” in Run window.
•Once it opens search the registry files related to Adware.Multiplug/Variant and delete all of them.

Step 4:
•Search all the Adware.Multiplug/Variant related files manually in your system and delete them.