|Try downloading Malwarebytes from another trusted source like FileHippo|
You may still need to boot in Safe Mode w/ Networking. Restart your computer and continually press F8 at the manufacturer's logo. This is the screen before the Windows logo. You'll have 3 Safe Mode options among a few others, so select Safe Mode w/ Networking. This will load core programs for Windows to run and your network card. Most malware don't get started, but some can add themselves to the core files and still work in Safe Mode.
Another awesome program is Super Anti-spyware, and it comes in a portable version. Download it from another computer, add it to a blank flash drive (don't want to risk infecting other files you have saved on it), then plug it into the infected computer and run a full scan.
Some tricky malware know the file names of anti-malware programs, so you may need to rename the executable (.exe) to something ambiguous.
Apologies if I don't respond to your reply immediately. I don't check this site daily, but you're welcome to PM me as a reminder.