Bad HDD?
My 2007 intel dou core iMac is running VERY slow. I have run the DU from start up and it shows that the S.M.A.R.T. working and the drive is verified. I also ran the repair disk, found 1 prob and fixed it and ran repair permission. I ran the AHT from start up and it shows a "4mot" (I may not have that correct) but it relates to a HDD fan so I downloaded a SMC fan control and bumped up the speed of my HDD and processor fans. I went back to start up and reloaded OSX Mountain Lion from Internet. I also replaced my 2gb ram with Apple 4gb. I am doing this post on my iPad because trying to type on the iMac takes forever. The pin wheel of death is everywhere.
iMac, OS X Mountain Lion (10.8.2), 3 gb ram, 750gb hd