A colleague just visited a site which had been hacked by the JS/Alescurf.C trojan virus, which infects HTML via embedded JavaScript.
Windows PC's are infected by visiting the site.
If my colleague has Windows Essentials, which detected and removed the trojan, is there anything else that he needs to do to make sure the virus is no longer active?
Windows Essentials detected the trojan within seconds of visiting the site, and he's running a full system scan to see if it still detects anything.
This signature is unknown to me and there is no trace of it in 5 largest definition databases. Are you sure that you typed it right?
In any case, your best bet would be a virus removal tool, I reccomend free utilities by kaspersky, they contain their latest virus definitions and a full scale antivirus engine:
http://www.kaspersky.com/virusscanner
P.S. Microsoft Essentials can't handle some of the viruses because lacks sophisticated security components, needed to catch them. If you don't want to run into such problems again, consider bying an industry standard endpoint software by either McAffee, Kaspersky or ESET.
A nice and clean scan with Malwarebytes Anti-Malware Free should work and check if everything is all right.
I recommend using Mcafee's Stinger and Microsoft's Malicious Software Removal tool which both are aimed at removing most of the in-the-wild viruses.
