That sometimes is a corrupt download. But just in case it's malware, we'll do it a little diferently and from safe mode please. So after the download, please boot to safe mode and run combo-fix .exe from there.
First delete the copy of combofix.exe you have, then procede.
It is vitally important that combofix is renamed before it is even started to download
Please download ComboFix from Here (http://subs.geekstogo.com/ComboFix.exe) or Here (http://download.bleepingcomputer.com/sUBs/ComboFix.exe) to your Desktop.
**Note: In the event you already have Combofix, this is a new version that I need you to download. It is important that it is saved directly to your desktop**
- If you are using Firefox, make sure that your download settings are as follows:
-Tools->Options->Main tab
-Set to "Always ask me where to Save the files".
- During the download, rename Combofix to Combo-Fix as follows:
(http://i266.photobucket.com/albums/ii277/sUBs_/combofix/CF_download_FF.gif)
(http://i266.photobucket.com/albums/ii277/sUBs_/combofix/CF_download_rename.gif)
- It is important you rename Combofix during the download, but not after.
- Please do not rename Combofix to other names, but only to the one indicated.
- Close any open browsers.
- Close/disable all anti virus and anti malware programs so they do not interfere with the running of ComboFix
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- Close any open browsers.
- WARNING: Combofix will disconnect your machine from the Internet as soon as it starts
- Please do not attempt to re-connect your machine back to the Internet until Combofix has completely finished.
- If there is no internet connection after running Combofix, then restart your computer to restore back your connection.
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- Double click on combofix.exe & follow the prompts.
- When finished, it will produce a report for you.
- Please post the "C:\ComboFix.txt" along with a new HijackThis log for further review.
**Note: Do not mouseclick combofix's window while it's running. That may cause it to stall**