Check if file is in use

Hi,
Is there a way to check if file is in use?
For e.g. how to check if a sample pdf file is open (adobe reader/browser)
There are several threads on stackoverflow and social.msdn.microsoft.com with possible solutions but none of them works as reported by other users (including me). (for e.g.  http://stackoverflow.com/questions/876473/is-there-a-way-to-check-if-a-file-is-in-use)
If we can't check if a file is in use, is it possible to override the sharing violation error and delete the file?
Thanks.