jerky video

Suddenly, my video playback is jerky. I've got an i7 processor and 9gb of RAM.

Yes, I know I can restore a prior version of the OS, but I'd really like to find out what is going on and fix it directly.

The sound suffers no interruptions, but the video hangs. The hang happens on a fairly regular basis (7 seconds or so), so I suspect some process is running, grabbing everything, and then releasing it.

The problem is not time of day dependent. And, my entire setup NEVER had this problem before - even with a slower machine.

Please suggest tools I might use to ID the problem; or settings I might play with to see if that helps.

Can you fill out more of your specs for us to get an idea on what's going on?

I also suggest downloading and running this tool. Give the page a good read too.
DPC Latency Checker

Have you updated your video card drivers?
Try the basics - update your drivers (mobo, add-on cards etc), install the latest DirectX version

Hope this helps
Regards

I loaded a new driver for the graphics card - no change.

I watched task manager and noticed that the nature of the video hang closely matched the refresh speed of the Task Manager. When TM was refreshing FAST, the delay was short. When TM was refreshing MEDIUM, the delay was longer. I also noticed that when the video hung, TM refresh hung too. This was obvious only when refresh speed was fast. I couldn't tell when TM was medium.

I then realized I hadn't tried a different browser. I had been using Firefox and when I switched to Chrome - no hesitation - so far.....

....But, as soon as I posted this, I got hesitation (worse than ever) in Chrome.

New Flash Player download might have done it. Can't be sure for a while, but a short test ran without a problem.

The problem remains.
I think it's my ISP. In this rented Florida apartment, you pay $35/month for a 1mbs link.
Just doing basic browsing, everything is snappy and then, every so often web access becomes non-responsive. If I hit refresh every 3 seconds, it's easy to see the recovery of the service - getting further every time.
Then, everything is zippy until the next choke.
For streaming videos, it's a bit a function of the player. I watch TV from ABC, NBC, CBS, Fox and via Xfinity. They all jerk a bit, some more than others, and each somewhat consistently.
During prime time, they also will stop dead (less frequently) requiring me to refresh the page and sit through another 2-4 minutes of commercials to get back to where I left off (Xfinity does return me relatively quickly and automatically to the RESUME location)
So, maybe it's not my laptop after all.
BTW, I never ran the Latency Checker suggested by Electrotune, but I did just mark the link and will read it at some point.