'Explorer has caused an error in IUSETUP.DLL'

Ok, I would assume that this is from spyware, however, after running every program to clean my computer in existence, every time I boot up the computer, I get this same error, so I imagine that I'm going to have to clean it out manually (it's not in any /WINDOWS/SYSTEM folders or areas similar to that). I've attempted clearing my cookies, deleting miscellaneous items through the Registry Editor, etc. etc. Would there be any way to remove IUSETUP.DLL without harming my computer/restoring from a previously saved boot date (through the BIOS)? And would it be accessible through the Registry Editor? As of right now, the error window doesn't seem to affect my computer that much (I just move it to the very bottom of the screen and try not to think about it, hah), with the exception of not allowing me to open the Task Manager and not allowing some programs to run. Any help would be greatly appreciated.