One thing I will say without question, each and every one of the infected .zip files, infected with Win32/TrojanDropper.Delf.NFH trojan listed in the ESET log are the result of P2P file sharing. I checked every one of them so that is how the computer has become infected, P2P file sharing.
This is why I asked you in post #3 to fix that one Shareaza entry. Looking at your combofix log I see that program was installed on 10-24-2008.
After that date I see multiple games and other paid programs installed, how many of these were acquired using P2P file sharing? Frankly I would find any program downloaded via P2P as suspect, expecially any installed after that date.
The ones we know for sure are infected files were installed on 11-15-2008, that honestly at this point doesn't mean there aren't others that haven't been found yet.

Yes, I want you to run combofix again. Follow THESE instructions EXACTLY:
At this point you should do the following:

* Close all open Windows including this one.
* Close or disable all running Antivirus, Antispyware, and Firewall programs as they may interfere with the proper running of ComboFix.

Once these two steps have been completed, double-click on the ComboFix icon found on your desktop. Please note, that once you start ComboFix you should not click anywhere on the ComboFix window as it can cause the program to stall. In fact, when ComboFix is running, do not touch your computer at all and just take a break as it may take a while for it to complete.
Windows may issue a prompt because ComboFix does not have a digital signature. This is perfectly normal and safe and you can click on the Run button to continue.
ComboFix is now preparing to run and when it has finished you will see the Disclaimer screen you should press the number 1 key and then press the enter key to continue.
ComboFix will create a System Restore point so that if any problems occur while using the program you can restore back to your previous configuration. When ComboFix has finished creating the restore point, it will then backup your Windows Registry.
Once the Windows Registry has finished being backed up, ComboFix will disconnect your computer from the Internet. Therefore, do not be surprised or concerned if you receive any warnings stating that you are no longer on the Internet as your connection will be completely restored at a later stage in the program.

ComboFix will now start scanning your computer for known infections. This procedure can take some time, so please be patient.
While the program is scanning your computer, it will change your clock format, so do not be concerned when you see this happen. When ComboFix is finished it will restore your clock settings to what they were previously. You will also see the text in the ComboFix window being updated as it goes through the various stages of its scan.

When ComboFix has finished running, you will see a screen stating that it is preparing the log report
This can take a while, so please be patient. If you see your Windows desktop disappear, do not worry. This is normal and ComboFix will restore your desktop before it is finished. Eventually you will see a new screen that states the program is almost finished and telling you the programs log file, or report, will be located at C:\ComboFix.txt.
When ComboFix has finished, it will automatically close the program and change your clock back to its original format. It will then display the log file automatically
You should now post this log here when all is complete.