Here is a download to uninstall Flash Player:
Here is a link to older Flash Players that you can install in replace:
Scroll down to the Flash player archives section, many versions are available. Please choose the "Release" version of any version you try.
hey, i just tried disabling hardware acceleration and even did it by right clicking on a youtube video, but no change, i just don't understand where they messed up, they always claim to have fixed their bugs and everytime it just got worse, i think they really need to jump back to like 10.1 with a few of the added features for the more modern devices, but get rid of whatever fixes they claim to have done since then because that seems to be the issue, maybe those people that requested fixes had a serious issue with their own PC and like 50 toolbars on their browser and it wasn't the flash for them, but i know for a fact that it's the flash player in the case
The jump to FP11 was pretty significant with Stage3D. Now Flash Player has a lower level access to your computers GPU to offload playing video and 3d rendering to the GPU. However if your systems GPU isn't up to the task you really won't see that performance gain.
Enter H264 video decoding. A large segment of the Flash usage market is simply viewing video. For sites without fallback in mind (or don't mind software rendering fallback), video may suffer. Using the GPU accelerated video classes may make it difficult for your system to view playback. Disabling hardware acceleration as recommended above would revert you back to software (CPU) decoding to check if your system itself is the issue (and not all the new GPU additions). You did that yet you're still having an issue.
Just to clarify, as I have an eMachine (for accounting), your computer is very much in the "budget" margin. You have a 3 year old single core 1.6ghz AM2 CPU with 512kb of L2. That's the K8 series. This is a very underpowered, single thread loving CPU. Only the most optimized Flash sites and lower end videos (720p or below) should play, but I'm not even sure if they'll "play well". It depends on your GPU.
Also you should know they have an official list of unsupported chipsets and drivers based on many factors. Here's a list for FP11 and AIR3:
Check the bottom of the screen to see what Flash is reporting your rendering mode is. For example, mine states:
Your gpu supports Stage3D in both Baseline and Constrained profile!
DirectX9 (Baseline Constrained)
This probably won't get better in the future for you. Flash is not a low end multimedia runtime. It does require and utilize high end hardware in a much more reliable way.