Boot up from a Mac OS X disc and remove the shapeshifter stuff. A lot of the time new stuff is put in /Library/StartupItems. If it's not there, try searching for shapeshifter.
If you only have the installer cd, which I don't think lets you access your files then try booting while holding the shift key down. That's sort of the Mac equivalent of safe boot. Then remove shapeshifter.
If you only have the installer cd, which I don't think lets you access your files then try booting while holding the shift key down. That's sort of the Mac equivalent of safe boot. Then remove shapeshifter.