Icons disappeared!!!

Hello!

After updating to MAvericks, most of my Launchpad icons have disappeared!!!

Also, sometimes the same happens to my Dock's icons!!! Also, the search bar at the top of the screen doesn't work when the icons disappear!!!

I tried, Disk Utility, safe boot, PRAM reset, re-installing OS X Mavericks and nothing seems to work!! Is anyone having the same trouble taht I have??

More: after installing OS X Mavericks on Mac OS X Lion, my MAc got a lot slower!! After installing it on Mac OS X 10.6, my Mac worked a LOT better!! Is Lion buggy, or what?!

Thanks for any information you may provide me!

Best!