Hi. I know the root of this problem isn't actually mup.sys. It's actually the process after it. But, what I'm wanting to know is how to solve my problem. Here is my problem: I recently purchased a Belkin Firewire/USB combo card and put it in my PC. It was working fine until I tried to use it's firewire capabilities. Clearly, my computer doesn't have the drivers or something it needs for this work. When the PCI card is in, I can't actually boot up my system properly. I just freezes when looging on, or on 'Mup.sys' when trying to boot safe mode. How can I somehow bypass whatever it is, and hopefully try and solve the problem in windows.. OR is there another solution? (other than formatting or buying new hardware, etc..)