security tool malware

Help! I have security tool malware (even though I have free Avira) on my laptop and cannot remove it because it won't let me download anything or even open windows explorer. What do I do? My desktop PC is fine and I can read advice here.

Please download the current version of HijackThis from HERE

• Double click and run the installer.
  
• It will install to C:\Program Files\Trend Micro\HijackThis\hijackthis.exe
  
• After installing, you should get the user agreement, press accept and Hijack This will run.
  
• Select Do a system scan and save a log file. This will open a notepad file of everything Hijack This found, copy and paste it back here.