HTC desire S won't play YouTube videos properly

[MikeyWalsh]

My HTC desire S has a problem: it won't play YouTube videos properly. The sound is staggered, and the picture quality is poor and freezes and changes every few seconds. So basically any video i try to view is unwatchable. Also after i try and watch a video, the image left on the screen as i leave youtube sticks on the phone, so every time i move from screen to screen on other aspects of the phone, this image from youtube appears for a split second. It's really annoying. Any ideas on how to fix this problem? Thanks.

(& Also, what happens to the phone if i restart it? Do i lose my contacts and other data on the phone?)

[Gonzo]

It might be a problem with the internet download speed, provided by your mobile network service provider. Check if any other software in the mobile phone is using network data continously, if so then immediately terminate its process. Also call your service provider and find out what download speed you are getting on your mobile phone to surf the internet. If you are low on speed, then the youtube videos are not freezing but it could be buferring and unless it gets good internet speed the video will just start and stop randomly.