External Harddrive problems deleting

I have Storage Vantec External Harddrive hooked up to my Dell with Windows XP
and it won't let me delete a lot of old files i have stored on there that are taking up a way to much space.
anybody know how i can fix this problem?

 

You could try checking there properties to see if they're write protected or read only and change that aspect of the file or use the freeware "Unlocker" to remove any delete restrictions from the files before attempting to delete them.