Windows 7 can be a serious pain in the ass when deleting files. This may help:
- Take ownership of the file(s). Start a Command Prompt (cmd) as an administrator in the affected folder, and enter:
takeown /f file takeown /f directory /r
- Give yourself full rights on the file:
cacls file /G username:F
cacls can be used with wildcards and directory traversal: Security from the command line with CACLS.