file cannot be deleted

Hi, I am using W2003 server in a desktop machine.
Some days ago I tried to delete a corrupt large .avi file and got a response that the file could not be deleted beacuse it was used by an application. I closed all programs , restarted W, etc but still cannot delete the file.
Since that day I have a very bad system performance, file browser hangs up from time to time, etc.
What should I do to find out what's happening?

Thanks,

Diego

As to the deletion:

This program will delete just about anything:

http://www.jrtwine.com/Products/DelF...lesInstall.zip

As to possible file corruption:

If you have a system disk, insert it, & go to start | run | (type) sfc /scannow

as for the deleted file you will need this program ... install it and then run it (should be an icon in taskbar) go to the file choose delete then after the message comes up with cannot deleted click ok then unlocker program will come up with the programs that are being used with the file u can choose either to delete/copy/cut then choose all of the programs used by it and click kill process and then it will be deleted

download site :
Download Unlocker 1.8.7 - FileHippo.com

You also try to boot into safe mode.

try this:
in command prompt, del /f /a:h /a:s yourfilename

Thanks for your sharing. Thanks for sharing this useful information. It's great.