If none of your security applications (including an antivirus or antispyware program, Malwarebytes Anti-Malware, or Malwarebytes Anti-Rootkit) will run, it is possible that you've been infected with something that is preventing these applications from running. Typically this is a rootkit infection, and can be very difficult to remove. Luckily, we have created a specialized version of Malwarebytes Anti-Rootkit that can help remove these threats. This tool can be downloaded from this link: Malwarebytes Anti-Rootkit Supplement
Once you have downloaded the tool (contained in a .zip folder), you will need to extract the contents. We recommend extracting to your desktop. If you are unsure how to extract the contents of the .zip file, please see this tutorial from Microsoft: How to extract zipped files
After the files are extracted, double-click the mbar.cmd file. If you are unsure which file this is, try double-clicking both files named mbar - only one of them will run.
Once the tool launches, follow the on-screen instructions to perform a scan with Malwarebytes Anti-Rootkit.
Only advanced users should remove infections by themselves - if you do not feel comfortable with this, please create a support ticket and we will provide you with guided instructions.