The primary cause of slow or unstable PC performance is disk fragmentation. IObit SmartDefrag helps defragment your hard drive more efficiently than any other product on the market ?? free or not. Features of this powerful, award-winning defragmenter program include: An "Install It and Forget It" feature that works automatically and quietly in the background on your computer. The ability to constantly keep your hard drive safe, error-free and running at its top speed and optimum performance. Eliminates slow downs, freeze-ups and crashes.....(free).....