PNG assosiation error

[plasmoidmonkey]

So, GIMP messed up my laptop, and now PNG files won't appear in internet explorer, even though I unistalled it. I've managed to find out that it's a file assosiation error, and I downloaded the file to fix it, but everytime I try to run it it says:

"Not all data was successfully written to the registry. Some keys are open by the system or other processes."

A system restore won't do any good, because I don't have any restore points from prior to the problem, unless someone knows how to set them backwards in time.