security tool infected cannot open computer on safe mode for removal

have loaded spy removal programs but unable to get computer to open on safe mode by pressing f8 instead a boot window opens with a hard dr or cd option. have tried numerous times without success. the security tool remains in control of my computer and has successfully evaded all efforts to delete it. can anyone help?

Download OTL by OldTimer to your Desktop.

• Close all windows and double click OTL.exe
  
• Click Run Scan and let the program run uninterrupted
  
• It will produce two logs for you, one will pop up - OTL.txt, the other will be saved on your Desktop - Extras.txt. Post both logs in this thread.
  
• You may need to use two posts to get it all.