Am I asking for trouble?

I was getting random BSOD's from a driver called US40fs64.sys so I just renamed it to US40fs64.old and things are working OK so far. I can't find any listing of what that driver actually does. Could I hurt my system by renaming it this way? So far, it seems to have helped.

If this fixed your problem, it was obviously a faulty driver. You can't find it easily, so it's not an important one.

When windows is unable to find a driver, it uses it's own standard one or it disables the device completely. Try opening Device Manager and look for faulty devices/drivers. Look if you can remove/reinstall/update/enable them. The BSoD's stopped, so there shouldn't be a problem.

Driver Reference Table

"Everstrike" to hide files? Rootkit? Virus? DRM? Games? Win8 support?

Like I said, there should be no problem. You can always scan your system for malware by using anti-malware bytes. Give that a shot if you're unsure about the health of your system.