Hello, welcome to the Myantispyware forum.
If you have previously downloaded ComboFix, please delete that version now.
Download Combofix from here
. Close any open browsers. Double click on combofix.exe and follow the prompts.
When the tool is finished, it will produce a log for you.If the log does not automatically open, then it can be found at %systemdrive%\combofix.txt (typically C:\combofix.txt).
Post back with combofix log.
If ComboFix will not run, please rename it to myapp.exe and try again!