Jenny100 my computer has 4 GB of RAM but when it comes up and displays specs it shows 3.25 GB Ram. Why doesn't it say 4 GB Ram?
That's normal for computers with a 32-bit version of Windows.
Sometimes they show 3.25 GB memory, sometimes a little more, but 32-bit Windows can't detect all 4 GB of memory.
Is this a Dell computer? When Vista was released, Dell used a 32-bit version of Vista instead of 64-bit because the 32-bit version was causing fewer issues at the time.
Could one of the memory cards be bad or one of the memory slots be bad? When removing one memory card at a time to check it still had corruption of picture and freezing after a few minutes.
Corruption of the picture suggests it's the video card to blame.
At one point i did get this message: "Display driver nvlddmkm stopped responding and has successfully been restored"
That message also suggests the video card to blame.
Even though it seems to be blaming the driver, it's most likely the card itself.
Could it be something wrong with the video card?
Yes, it sounds like the video card is failing.
When you look for a new video card, make sure there are 32-bit Vista drivers available for it.