Whenever I start playing a video on my ubunt10.10 on players like vlc or totem the whole system hangs abruptly and mouse and keyboard are become unresponsive but audio still plays. Can any one please help me..
This problem usually occurs when the hard disk drive is having a failure, necessarily physical.
Somehow the drive is experiencing an issue when trying to get the buffering from the video in the hdd, this can be caused by delays in the hdd and/or bad sectors allocating data.
For a test: If the problem is happening exclusively in a single file, please make an exact copy of the file, then try to run the new file, if the problem persist in the new copy then you are experiencing a problem with your codecs (try installing/updating (removing/reinstalling) restricted extras). If you are absolutely sure that there is no problems with the codecs try using a lighter video player (dragon player and gnome player come to my mind).
If your problem is happening with whatever video you choose from your hard disk drive, then you may be experiencing a major problem with the delays on your hard disk drive. Then I will recommend the usage of a tool like HDD Regenerator in order to check the HDD performance and determine if there are sectors failing/delaying and they can be recovered.
WARNING! The usage of tools like HDD Regenerator will result in the loss of data if you run the process directly in the HDD without backing up/cloning your partitions/disks. Make sure you do a complete BACKUP/CLONING before running this tool.
HDD Regenerator will erase everything in your hard disk drive in order to do the needed changes so you can redo from start again.
Based on your comments to this answer I can change parts of this in order to provide further support.