video picture and voice out of sync

Hi,
Please someone Help.
have several players on pc (divx, realone, ultra, media ect) but no matter what I play on any player they are all play film and sound comes 15 seconds later.
I’m sure I need a codec but every one I have tried doesn’t make any difference.

Two common causes:
1. The person who encoded the video did a poor job. It’s not common, but it happens. (one example was one of the original rips of the paris hilton movie, but I digress...)
2. The computer you’re using is underpowered. Modern codecs (like divx, windows media video 9, h.264) take a lot of processing power to render video, and if your processor is old, frames will be dropped, audio and video will fall out of sync, the scene may seem to freeze. Video freezes more often, since video codecs take a lot more processing power than audio codecs. One easy way to check if you’re using Windows 2000 or XP is to look under your task manager. Right click your taskbar, then choose task manager. Look under performance. Is cpu usage at 100% while the video plays? if so chances are it’s choking on decoding the video. There’s not much that can be done except get a newer processor. You can also try to allocate as much cpu power to video playback by turning off and closing all unnecessary tasks (instant messengers, file sharing, anything in the taskbar, and (for advanced users only) services). Also disable post-processing and film effect if the file uses the divx codec. Finally another way to check if the processor is underpowered is using virtualdub. if the file plays in virtualdub in slow motion then your pc is underpowered. virtualdub is also a good way to view the movie without freezing/dropped frames (if you don’t mind slow-motion video and inaudible audio)