can i delete WinATS.dll if infected by trojen horse

Yes, but it will most likely reinstall itself. If you would like some help do the following: Please post a Hijack This log so that the files associated with the virus/spyware/hijacker can be identified. Please download HJTsetup.exe from this link http://www.thespykiller.co.uk/files/HJTsetup.exe to your desktop. Doubleclick on the HJTsetup.exe icon on your desktop. By default it will install to C:\Program Files\Hijack This. Continue to click "next" in the setup dialogue boxes until you get to the "Select Addition Tasks" dialogue. Put a check by "Create a desktop icon" then click "Next" again. Continue to follow the rest of the prompts from there. At the final dialogue box click "Finish" and it will launch Hijack This. Click on the "Do a system scan and save a logfile" button. It will scan and the log should open in notepad. Click on "Edit > Select All" then click on "Edit > Copy" to copy the entire contents of the log and post it in this thread. Do not fix anything yet unless you know what you are doing. This is a powerful tool that can crash the computer if used improperly.