It depends... you may have a balance with the companies administrator.. or depending upon their vesting schedule.. you may not.. (some companies require you work there so many years before any employer money is actually yours....) Did you ever get any statements? the money is somewhere if there is any.... if you have a statement call the company it came from.... it will either still be there... or they would have had to move it to an IRA w/ a third party administrator...
Do you have contact with anyone else that had the same plan?

Thank you for your valuable answer,it kind of answered my question .But not quite can you help me a little more?To answer your question , I actually dont have contact with anyone from the company, and it actually went bankrupt. Does that make a difference at all?

The company themselves did not (most likely) administer the plan. What company did you get your statements from?