No expert here, but when you installed Windows onto this hard drive, did you install the correct video drivers? You said you have been upgrading the system over the years, and if you have changed the video card then that 'old' Windows XP install CD, (or the drivers CD if that is separate), will not have drivers for the new card.
Mark
I bought my computer off of a friend years ago and have slowly been upgrading it over the years. The only piece I hadn't upgraded was the 80gb hard drive which when scanned said it was in bad condition and may crash at any time - yikes!
So, I went out and bought a Western Digital Caviar Black 1tb drive. I installed it in my machine, and installed Windows XP Pro for a fresh start. The install went fine, but once the OS booted up, I noticed that program windows weren't moving as smoothly as they normally do - my mouse moved slowly, but the program windows were really jittery. I also noticed a similar problem when scrolling in internet browsers (both IE and Firefox), instead of a smooth scroll, it was jittery.
Aside from the hard drive, the hardware is exactly the same as my old setup. I even booted from my old drive and it ran smoothly as usual.
Do I have a bad hard drive, or is there something else that could be the problem

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