If your computer was infected with Netsky.B it is unlikely that it did any damage to your system as it is a mass mailing worm, and is not destructive. See for yourself at
[email protected]" title="http://securityresponse.symantec.com/avcenter/venc/data/[email protected]" TARGET="_new">click here . It sounds like either you had another variant of the virus/worm, of the guy you had fix your computer managed to delete something important. Removal of this virus is incredibly easy, so I would complain to whoever fixed your computer that as they don't seem to have done a very good job!