thanks for your suggestions,but how do i perform these tests when the windows is not even loading in atleast safe mode also,i tried your other solutions like removing the connectors and connecting again,but it did not work,the memory stick is fine,i have tried on the other computer and its working ,i feel its a windows problem and it may have to be reloaded again after formatting.

if you have any other solution pls let me know,anyhow thanks a lot for replying me