Client is trying to check out a workbook in sharepoint and it is telling him it has either been deleted or someone else already has it checked out. This happens for any workbook he tries to check out. So Client Deleted the cookies and cache and was able to check out the file but then it says "A copy of this file is checked out on another machine. The server copy may not contain your latest changes."Yashwanth

try having him run the microsoft office diagnostics tool under microsoft office tools

Problem is resolved..Thanks a lot..Yashwanth