Total Computer Takeover. Don't even have rights as Admin in Safe Mode

I'm working on one of my laptops, which was completely taken over. I am unable to install any antivirus software (running McAfee, but I've tried A-squared free, AVG, etc.) I also cannot install Java updates, or any other software. And as of today, I can no longer open/explore my disc drive. I've even tried creating a new admin account, but as soon as i log on as that admin, i get the same results. Please Help!!

Thanks

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.