Computer got infected, says it can't find mbam.exe

My sister was surfing on the net, and unfortunately the main computer was infected with a virus. Whenever I click Malwarebytes, it says it can't find mbam.exe. I need to have it removed quickly, since I am in the process of fixing my laptop, which requires the use of a clean computer. I need help on this matter, and preferably by someone in the USA who can respond quickly, since this is my spring break and I can fix the computer anytime you want me to. Thanks!

Is this a different machine than Chiaz is helping you with?

Yes it is, do you know how to help?

Thanks!

Okay, save this for later, finish up with Chiaz first and then bump this back up, it will be easier and less confusing for you.

I need a clean computer to finish the cleaning of the laptop. Apparently in the step I'm at. Or is this ok?