If a command-line approach is viable, and you're on a Linux-like system, then lsof
is your friend. There are about 10 gazillion flags for lsof
, but for your needs, it should be as simple as:
lsof myfile
You should get output similar to the following:
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
someprog 4660 foobar mem REG 253,0 58400 4522314 myfile
EDIT
You say you're using Windows. I'm not familiar with Windows command-line tools. However, here's a question that may help: How can I determine whether a specific file is open in Windows?.