AVG 7 has picked up a virus on my PC called Trojan horse clicker.BG but will not remove it

I have tried a couple of online scans and even installed NAV 2002 and none of these picked it up
The file it is in is called WinAdTools.dll and it is in the following file location
C:\Documents and Settings\David\Local Settings\Temporary Internet Files\Content.IE5\4ZQRID2X\bridge-c2[1].cab\WinAdToolsX.dll
The problem is I cannot find the file in Content.IE5, 4ZQRID2X to try and manually delete the file

There are 4 others in there of similar name but not that one. I have done a search for this file and the WinAdToolsX.dll and windows explorer will not find them! I guess these are hidden files/sytem files or something but I have already unchecked and checked the required boxes in folder option within My Computer to view hidden and system files (I am using XP Pro by the way) is there something I am missing to allow me access to this file. Please help I am fed up of stupid spyware etc