How to Remove a Virus From a Website

Avast Free Antivirus / Premium Security
1

I design websites.

I am redoing a site for a client.

Avast pops up stating:

‘avast! Web Shield has blocked a harmful webpage or file.’ whenever I open his current site, www.radiancephotographystudio.com.

I have access to his site through FTP. How can I scan his site and remove the offending file or files?

Thanks

2

site need new jomla http://sitecheck.sucuri.net/results/www.radiancephotographystudio.com

detected by AVG http://www.urlvoid.com/scan/radiancephotographystudio.com/

zulu http://zulu.zscaler.com/submission/show/c1c474221495655cb760bf8db6418fca-1403762887