avast can't detect this virus

today,my computer has been infected by unknow virus. hidden and lock real folder and make same name folder with ext.exe
ect. program files → accessories.exe

my computer using win XP Sp2, all program in start menu was hidden by this virus, this hidden folder can’t be normalize again coz the hidden file option was locked.
how to make release lock hidden file and the virus ?? :'(. i used avast. 4.7 with update vps 2-08-06 but can detect the variant

the virus it’s call wincfgs.exe
make windows.exe and folder.exe in all folder in computer.real folder was hidden and can be see in normal way… then locking the folder in hidden file

With XP you could enable a boot time scan. Right click the avast icon, select Start avast! Antivirus, Menu, ‘Schedule boot-time scan…’

A google search for wincfgs.exe returns many hits, http://forum.avast.com/index.php?topic=22568.0, http://www.sophos.com/security/analyses/w32delfcrk.html.