Virus Code Alert on my website files

Yesterday i take my website files backup on my PC. But when some files download, my antivirus software show virus alert. how can i fixed this issue in server. Now Google Webmaster also sent alert for malicious code found.

Unfortunately it can actually be quite difficult to find all bits of malicious code because they are designed to be hidden.

Probably your best bet is to find a developer who is experienced in this. They should be able to compare your website files to a fresh copy of the exact same version of OpenCart with a look like: http://meldmerge.org/ which can help them find it.

They can do the same thing with a fresh copy of your theme.

Once those things are removed, you have to submit a request through Webmaster Tools to get the virus warning taken off your site.