Do you have "hide protected operating system files" on in folder options? That might only apply if the folder has a system attribute set as well.
You might be able to access the folder from the command prompt to rename it. Here's how to try it. Open the command prompt. Click start, (all) programs, accessories, command prompt. You should be in your home directory: C:\Documents and Settings\yourusername\>
Type
cd my documents
(no quotes needed)
you said your folder had the blank character right?
type
attrib "<alt-shift-255>" -r -h -s
ren "<alt-shift-255>" somenameicanremember
be sure to put quotes around the null character, or the command prompt won't be able to interpret your command.
Hopefully this will make your folder visible again.
Note: I used the < > to delimit where the keystrokes should go - don't type in the < or the >!