Chas, Thanks for the reply. Firstly, i meant 'Preview', not 'Viewer'.
Unfortunately OnyX never found any problems with the disc nor the SmartStatus of the disc.
I tried to re-load the OS software disc to try and repair it that way, but it wants to completely remove all on my HDD with a brand new install.
Two things,
1. It might be an option and totally forget about reinstalling Mavericks as i believe this may be the problem.
2. If i did that, will the 'Time Machine' put back everything that i have on the Mac that i have at the moment, or does each item/folder have to be restored individually on the Time Machine?
Ive tried to restore the problematic icons with Time Machine, but it tells me... “Preview.app” can’t be modified or deleted because it’s required by OS X.". Which is crazy as its not working properly.