Everytime I open a new tab in Firefox or while I am playing Solitaire, I will get frlickering on my screen where the computer will not respond for a second... I was lost as to what the problem is.. I am running Eset Smart Security only which is the lightest on system resources, I have an i5 @ 2.93 GHz. with 8 GB DDR3 Ram and an ATI Radeon HD 5650 and the latest ATI Drivers so I was lost I googled this and someone had the exact same problem and it appears that disabling the Desktop Window Manager Session Manager solves the problem and now my laptop is much faster! Just wanted to share my experience incase it helps someone This disables the Aero visual interface but I don't give a crap about it really. It was nice at first but then you never miss it if it was gone!
Sounds like possibly bad GPU. Symptom resembles a bad GPU overclock in 3D Mark 2001 SE. (corruption and pauses)