Make sure the disk it not write-protected?

Trying to delete virus infected file, but always get this message :

Cannot delete file OR

Access is denied OR

There has been a sharing violation OR

The file is in use by another program or user. Make sure the disk is not full or write-protected and that the file is not currently in use.

Well, thanks UNLocker for saving the day & making my work much easier. There's no need to reboot the computer into safe mode to delete the infected file. It's just awsome!