Do I need special OS permissions to install and use the software?

To install Eraser software on Windows 95/98/ME you do not need special permission. To install software on Windows NT/2000/XP you need permission (i.e. as an Administrator or in the Power Users group). The same is related to erasing drives and devices. To erase files and activities you do not need any special permissions, unless the file is located on an NTFS partition. You must have permissions to "write" to the particular file in order to destroy it (you can not destroy the data if you do not have access to it).