Newbie's Trojan problem.... Please be Gentle with me!

Hello everybody. I am by no means an expert in this field, so I am looking for some answers from experienced people.
Norton Anti Virus informed me that I have a Trojan on my system.
The infected file is C:\Documents and Settings\[my name]\Local Settings\Temporary Internet Files\Content.IE5\UPSJKR2P\Dummy.class

Apparently, it is Trojan.Byteverify.

The problem is that the file is no longer there! I have searched for it with Windows explorer, and cannot find any files with that name anywhere. I have also done a full system scan with Norton, and a Full scan with Trojanhunter, and have turned up nothing. The only thing the Trojan seems to be doing is resetting my Internet Home Page to Smartsearch, and, bizarrely, everytime I open a program or new IE window, Windows Installer starts up and tries to install Microsoft Money. This does not go anywhere, due to the lack of a disk. I have got a couple of Trojans before,and have found and eradicated them with no problems, but this one is really annoying me. I am running Windows XP, if that helps at all.
Thanks in advance.

 

Hi lard0

Welcome to Wilders.

Sounds like u have a homepage hijacker on your system.

Please follow the instructions here,

https://www.wilderssecurity.com/showthread.php?t=15913

then post your HijackThis log in the hijack cleaning forum with a full description of your problem and one of the experts will give u recommendations on any Malware found. Also, clean out your temporary internet files.