|The infection is stopping the downloads, try this technique.|
Example, trying to download Malwarebytes.
Click on the download link, then rename it before you download it to your desktop. As you are in the process of downloading when you get to the point that the "enter name of file to save to" box appears, in the "filename" slot, rename mbam-setup.exe to something.exe, then click Save.
Another way, is to download the programs from a good comp & put on a thumb drive.
You still may need to rename it, the infection may stop the install, see how you go, there are other ways to outsmart the infection.