Click Start / Settings / Control Panel / Folder Option / View and select your choices.
If you do not see 'folder option' icon in your Control Panel, and you are using Windows ME, click on Start / Programs / Accessories / System Tools / System Restore and select a previous date to restore all your settings. This should re-establish the folder option icon.
Another option you might try is,
click Start / Run and type in scanreg /fix. Notice there is a space between the g and /. After it is done, shut down the computer, wait a couple of minutes and restart the computer then check for the 'folder option icon in your Control Panel.