Open a command prompt and rename it
cd parentfolder
ren "..(" dotdotparens
E.g.
C:\temp>dir
Directory of C:\temp
19/11/2010 17:51 <DIR> .
19/11/2010 17:51 <DIR> ..
19/11/2010 17:50 <DIR> ..(
C:\temp>ren "..(" dotdotparens
C:\temp>dir
Directory of C:\temp
19/11/2010 17:53 <DIR> .
19/11/2010 17:53 <DIR> ..
19/11/2010 17:50 <DIR> dotdotparens
However since ..( is a valid folder name which can be opened in explorer, there's probably more to the name than you've seen. The technique may still be useful.
Update: if you have perl installed, try this
C:\temp>perl -e "opendir H,'.'; while ($f=readdir(H)) { print qq($f\n) if $f=~/^\.\.\(/ }"
..(A
If the above prints a single folder, it is safe to proceed ...
C:\temp>perl -e "opendir H,'.'; while ($f=readdir(H)) { rename $f, 'xxx' if $f=~/^\.\.\(/ }"
C:\temp>perl -e "opendir H,'.'; while ($f=readdir(H)) { print qq($f\n) if $f=~/^\.\.\(/ }"
Update 19 December 2011
If you don't have Perl but would like to, you can download and install it.
If you want to check file or foldernames, you can use something like this
C:\test> dir
19/12/2011 16:49 <DIR> .
19/12/2011 16:49 <DIR> ..
19/12/2011 16:49 <DIR> ð
C:\test> perl -le "opendir H,'.'; print $_,qq(\t),unpack('H*',$_) for readdir(H);"
. 2e
.. 2e2e
- f0
C:\test> perl -e "rename qq(\xf0),'foo' or die $!";
The perl script provides a hex dump of the file or directory names so that you can work out exactly what they are and do something about them.