Open any folder, 'My Documents' for example. Then 'Tools' -> 'Folder Options' -> 'File Types'. Locate 'WMA' in 'Extensions' column and select it....
This should help with CoolWebSearch -> http://www.trendmicro.com/cwshredder/
A 21-day trial for removing duplicate contacts from address book, http://www.wbaudisch.de/WABCleaner.htm
'Hidden' is grayed out? That's because it's 'system' file.
Open 'My Documents' -> 'Tools' -> 'Folder Options' -> 'View' and select 'Do not show hidden files and folders'.
Separate names with a comma.