Malwarebytes probably won't help. As much as I like the software, at the end of the day there are people being paid to circumvent detection and hijack your PC, which is what this program does - holds your PC to ransom.
I find that the only true way to get rid of these things is manually. Like, boot up in safe mode, and use regedit to find the processes that run on startup - your 'virus' will be called something random, like random numbers or letters. Delete those, then go looking for similarly named files - usually in your documents folder, local settings. These programs will always be visible in the registry, edit the registry to get rid, and as long as the programs themselves aren't running you tend to get rid of them.
The online guides will have you doing pretty much the same thing, it's handy to know registries, especially the RUN section, where all the nasties tend to hide.
Health, Ammo, and bacon and eggs!
