I know it is not a memory issue, because I have enough.
Every time I go on Firefox, when I scroll down, a line moves down the screen, as if it was refreshing itself. This also happens when I move a window. Whenever I move a window, I get a screen stutter.
This may be a monitor problem, but I have a plug and play monitor. And now it say 'Default Monitor' under Settings. It has always said 'Plug and Play Monitor' I have a ViewSonic Graphic Series, G90F.
Also, this may be a graphics card problem. I try reinstalling my drivers to no avail of a solution. I have a NVIDIA GeForce FX 5700 LE.
As another reminder, this is all after I downgraded.