Hello tek tippers and thank you for taking the time to look at my problem. I have 3 gig of ram installed on a desktop(new build) its DDR2 667. When i run a memory testing software from within windows(software is pass mark version 5.3) i get error messages which say the data has been unable to be verified from within ram. The machine seems to run OK. When i run memory testing software outside windows(tuff test pro) which boots into its own environment i get the all clear. In the past i have found the tuff test pro software to be excellent in identifying memory problems so i am inclined to believe it. But my question is why does the windows based mem test report errors and the non windows software give the all clear?? All answers very much appreciated as I am very curious on this one.