Enabled "Hardware Acceleration" causes "green screen"

Hey guys.
Can you pleas explain me what does Hardware Acceleration means and why is that when it is turned on, it causes a green screen on the video (with audio working).
It happened to me once in YouTube, where I had to go in to settings and unpick the "Enable Hardware Acceleration", then it worked!
And 2nd time similar thing happened in Cyberlink PowerDirector 10, when I imported .mp4 and flv video files and it showed me green screen with audio. After unpicking "Enable Hardware Decoding " it was fixed.
My Sony VAIO has:
CPU - Intel Core i5 M430 2.27GHz
RAM - 4GB
GPU - AMD Radeon HD 6500M/5600/5700
Does this mean that I have a problem with my hardware, or maybe I need to set up something??? to ba able to use Hardware Acceleration. As I understand I should be able to use it!!??

Thank you
Have a nice day

I don't know what the problem is but the only time I had this issue is when I installed a VM and get black screen on youtube so I had to enable that.

I'd lean towards a Flash bug as it can happen with both AMD and Nvidia cards, seeing as it can happen for no real reason form one driver version to another. Could be the same thing with Power Director. Check at Sony for your model and see if they have an updated driver and try it. If they do and you already have it installed, uninstall and roll back to the previous driver you were using.

You can also try the one linked here,

AMD Catalyst 12.x (8.95 January 24) Unofficial BETA - Guru3D.com Forums

which has the Intel graphics driver integrated into it, so that the switchable graphics will still work. Seeing as that is a Sony laptop it may not install though, as Sony have a bad habit of not allowing drivers other than those they provide to be installed (through the use of different product ID's).

I have the most up to date drivers all the time, including AMD graphic drivers. I am updating them with Driver Genius Professional Edition and there is no problem to install any new version of the driver! I have never downloaded drivers from Sony website BTW.
My problem is that I have the opportunity to use hardware acceleration because I have graphic card and it is not bad, so why is it not working then, why is it showing green screen?
It's pretty good thing to have it's just sad that I have to turn it off in order to watch videos (in certain places)
Thanks
Still waiting for some help, if someone can explain?

so why is it not working then, why is it showing green screen?

Ask Adobe, they're the one's responsible for that bug ridden thing known as Flash.

Hp h8-1360t
Win7 Home Premium 64bit
Intel Core i7-3770 (quad core) cpu @3.4 Ghz
8 gig memory
AMD Radeon HD 7520 2gb ddr3 FH PCIe x16

Sorry to bump this thread. I am new here and this one seemed to be the closest to my problem. I have had this pc for about 8 months now. I noticed over the last couple of weeks, the video seemed to be slowing down or playing at a lower resolution. Today, I started getting the "green screen" everyone has been talking about. I disabled the "hardware acceleration", which allows the video to play, but it is still running slow and playing at a lower resolution.

If it makes any difference, I recently loaded Sony Movie Studio Platinum 12. I need to start working on a video ASAP.

Any assistance will be greatly appreciated.

It's a problem from recent Catalyst drivers (UVD part). The problem is specific for Radeon Mobility especially for HD5650. Fortunalty, a solution exist!
Guru3D solution : [GUIDE] Fixing video playback & overclocking problems. - Guru3D.com Forums