I have a Dell Optiplex 780, running Windows 7 pro. with 4 GB of RAM. Lately it has been very slow in processing, and the mouse was very hesitant, I made the decision to upgrade the memory to 4 more GB's by adding one Crucial memory bar which they scanned my PC, and then recommended as the correct bar. After installing the bar, I confirmed the addition in properties, and also ran the memory check test, throughout the test it said NO Apparent Problems and when it was at about 98% complete it restarted Windows. The machine is processing much faster! However I have had several auto shutdowns with a blue screen message saying there is a problem! and it was shut down to protect Windows 7, from being damaged, also several times when the PC was restarted, it sounded like a car engine on High Idle, and it kept running like that for way to long! and would not load windows. Something is definitely happening here, but Could it be with this New Memory Bar? ..and are there any further tests I can run to check it out? I am thinking about uninstalling the new strip and seeing if the problem stops! ..Any opinions would be much appreciated.