Hot Corners don't work/Click and drug doesn't work

Hi, I have two computers, iMac 2008 desktop (OS X 10.9.4 ) and Mac air book. Recently about 3 weeks ago. Both of them started having issues. When i will navigate in any corners they would not work (neither Screen Saver, nor All Applications) none of the hot corners that I set up work. However, at times they would work but really slow and my computer kind of like logging (getting supper slow) Another thing happened to both computers: When I click and drug any file from one folder to another it just would not do. the file I click would get hi lighted stick to my mouse pointer and the computer would just freeze. However, when I do copy and paste a file it works. I upgraded to Yosemite and even that did not help. I reinstalled OS X from my old time machine back to OS X 10.9.4 and the problem still persist. Is this disease a nation wide ???

Please help....

did anyone else had something ???