Virus Identified.Packed Hidden

hi friends
my pc is infected with virus.i m using windows xp(sp3) as my OS.
antivirus is AVG FREE EDITION.
avg has detected Virus Identified.Packed Hidden


\\?\globalroot\systemroot\system32\gasfkydqxqnku.dll
c:\windows\explorer.exe(1532)

after removing above threat from virus vault,virus reappears in scanning.
plz help
Thanks in advance