From the sound of it, it might be that you have a file with a "weird" character in its name that the Finder can't handle properly. The Finder is buggy like that.
If this is the case, you can fix it from Terminal, like this:
Look at the list of items that appears. If one has a weird-looking name, copy the name, and then type this:
mv ./<paste the name here> ./normal_name
That should change the name of the file to "normal_name" and allow the Finder to work again.