Right click on usb optical mouse

Have been using a Logitech usb optical mouse for quite some time.
Within the last week I suddenly don't have any right click options pop-up when I select a group of files. It still works with folders but not individual files to copy, send to trash, etc.
Any ideas? Using OSX 10.6.8 on Mac Pro.
I've been through all the menus and can't figure it out.

Well, I'd probably do several 'simple' steps for starters (if not already done), e.g. remove the battery and re-insert, check the battery, and also unplug the USB adapter and re-insert. If not successful, reboot your computer and check the mouse on another computer. Good luck and let us know your results -