There is a simple check that can be done to see if any computer in the office is infected with the conficker / downadup worm / virus. When a computer is infected it is blocked from accessing certain security related sites. The following 3 sites I've heard are among those blocked.
This is just another level of checking. Your antivirus should keep the infection out and you can also use
nmap 4.85 beta 6 or newer to detect the presence of the virus / worm in a LAN using this specific scan:
nmap -sC -p 445 -d -n -oA conficker_scan -PN --script smb-check-vulns --script-args unsafe=1 192.168.1.1-254 (use your ip range here)
or
nmap -sC -p 445 -d -n -oA conficker_scan -PN --script smb-check-vulns --script-args smbdomain={your domain},smbuser={domain admin},smbpass={password},unsafe=1 192.168.1.1-254 (use your ip range here)
nmap is a great free tool as it can very quickly scan a whole
subnet for a variety issues. The biggest hurdle is learning the many options for scanning on the command line. You can also use
zenmap the windows GUI interface to the tool.