I have a new iMac and was going to give my old powermac away to a local charity. I used the old mac quite a bit for financial transactions including banking, mortgage payments, etc. I was told to be careful because all this information remains on the hard drive. If I erase the hard drive, is all that information truly erased from my system or should I just destroy the computer and not donate it? Or, if erasing the hard drive doesn't truly erase, is there a software package that eliminates old information from macintosh systems? Thanks.