BleepingComputer.com: Trojan won't delete (Trojan.PWS.Agent.SHZ) [Moved]

I replaced my old antivirus (AVG) with Bitdefender today, and no sooner had I started the program than it threw up a virus alert, saying it had detected and deleted a virus - Trojan.PWS.Agent.SHZ. As soon as it told me that, it did it again - and again, and again, and again. The infected file seems to be "xocgme.sst" in the Windows folder, but it constantly replaces itself as soon as it's deleted, whether by me or Bitdefender, adding an "x" to the end of the file name each time. I can't find much about this trojan on the Internet (unless I'm not looking properly), and Bitdefender's constant alerting and deleting is slowly the computer down dreadfully. What can I do to get rid of this trojan for good?

As no logs have been posted, I am shifting this topic from the specialized HiJack This forum to the Am I Infected forum.

==>PLEASE DO NOT NOW POST LOGS<== unless a log is specifically requested.

Hi and welcome to BleepingComputer

The process of cleaning your computer may require temporarily disabliling some security programs. If you are using SpyBot Search and Destroy, please refer to Note 2 at the bottom of this page.

Please download Malwarebytes Anti-Malware and save it to your desktop.
alternate download link 1
alternate download link 2

• Make sure you are connected to the Internet.
  
• Double-click on mbam-setup.exe to install the application.
  
• When the installation begins, follow the prompts and do not make any changes to default settings.
  
• When installation has finished, make sure you leave both of these checked:
  • Update Malwarebytes' Anti-Malware
    
  • Launch Malwarebytes' Anti-Malware
  
  
• Then click Finish.

MBAM will automatically start and you will be asked to update the program before performing a scan.

• If an update is found, the program will automatically update itself.
  
• Press the OK button to close that box and continue.
  
• If you encounter any problems while downloading the updates, manually download them from here and just double-click on mbam-rules.exe to install.

On the Scanner tab:

• Make sure the "Perform Quick Scan" option is selected.
  
• Then click on the Scan button.
  
• If asked to select the drives to scan, leave all the drives selected and click on the Start Scan button.
  
• The scan will begin and "Scan in progress" will show at the top. It may take some time to complete so please be patient.
  
• When the scan is finished, a message box will say "The scan completed successfully. Click 'Show Results' to display all objects found".
  
• Click OK to close the message box and continue with the removal process.

Back at the main Scanner screen:

• Click on the Show Results button to see a list of any malware that was found.
  
• Make sure that everything is checked, and click Remove Selected.
  
• When removal is completed, a log report will open in Notepad.
  
• The log is automatically saved and can be viewed by clicking the Logs tab in MBAM.
  
• Copy and paste the contents of that report in your next reply and exit MBAM.

Note:
-- If MBAM encounters a file that is difficult to remove, you may be asked to reboot your computer so it can proceed with the disinfection process. Regardless if prompted to restart the computer or not, please do so immediately. Failure to reboot normally (not into safe mode) will prevent MBAM from removing all the malware.

Note 2:
-- MBAM may make changes to your registry as part of its disinfection routine. If you're using other security programs that detect registry changes (like Spybot's Teatimer), they may interfere with the fix or alert you after scanning with MBAM. Please disable such programs until disinfection is complete or permit them to allow the changes. To disable these programs, please view this topic: How To Temporarily Disable Your Anti-virus, Firewall And Anti-malware Programs