Q: Hi i have mac os x and suddenly the track Pad even though the cursor is moving i cant click on anything through the track pad..

Is it possible that the trackpad has simply failed, or has gotten some grit underneath?  That's a mechanical problem, and generally solved through disassembly and potentially replacement.  

I've very occasionally had some success clearing grit by cleaning the trackpad, and gently but firmly running my finger around while pressing down at the extreme edges of the trackpad.

If the problem persists, this usually involves a trip to the Apple Store or to whomever you are using for repairs.

There is a setting for the trackpad that you can test with — connect and use an external mouse to access the settings — via System Preferences > Trackpad.  See if enabling the tap-to-click setting helps here, if you don't have that checkbox enabled.  That avoids using the physical button underneath the trackpad, if that underlying switch has failed or has jammed.

For completeness, there's also a System Preferences > Assistive setting that disables the trackpad entirely when an external mouse is connected, though that disables the entire trackpad — you're reporting the trackpad is partially working and moving the cursor, but not clicking.  Which implies this setting is not a factor.

On Mavericks, it's the function key that enables dictation.  Not the option key.  That setting also does not effect the behavior of the trackpad.