Windows 7: Question About Videos

I have an Acer Aspire AS5551-4200 laptop, and ever since I got the laptop I have been having this problem. I've gotten used to the problem but was wondering what would cause the issue.

It don't matter if I am playing Blu-Ray movies, DVDs, or watching MP4 or other video files on the laptop, there is a brief 'stall' on the video even though audio is working. It also happens when I initiate the internal webcam when I first turn it on.

My laptop came with Windows 7 Home Premium 64-bit, and I have all updates to date. I have updated drivers, and have updated directx. I still have the same problem. I saw on another forum where it might have to do with the brand of hard drive (Western Digital), and it's wanting to sleep that is causing the problem, but the file it gave me to download, I think it was fixhdd.exe or something, but it didn't work.

Any ideas?

Is this happening only in Windows Media Player? Or is it the same with say Quicktime and flash players in browsers?