Hi friends,
I am using XP. Recently I installed System Mechanic and after that the mouse functions went awry. Even after uninstalling the program I am unable to use cut and paste, drag and drop funcitons. I tried every trick in the internet. No help.
Anybody can suggest ways and means to restore these functionalities.

Another One Size Fits All computer problem solving software. Reading the site's explanation of what it can do is scary enough. Uninstalling the pgm would not help by itself, you should first have used its Reverse function to undo the damage [if it even could...].
You might try reinstalling your mouse drivers [do you have a cd for those?]. AS for cut n paste etc... sometimes malwares can disrupt those functions... try running MBAM [it certainly won't hurt]. Tried a Restore point? You've tried every other trick, so it's no point me suggesting any. Except a Repair, and those can hurt. If you have System Restore functioning then a recent restore point will be available to update the Repair's changes, but you still must download all Security updates again.

I suggest a systems restore back to before you had this program.