I am going to wipe my system before installing a new. I have an 80 GB Ultra ATA (4200 rpm), Intel Core 2 Duo U7500, 1.06 GHz, 2 GB DDR2 RAM. How much time will it take to wipe the whole disk? Can go anything wrong, i.e. can anything be destroyed so I cannot use the computer anymore, or will it always be possible to just put in my Windows DVD and install a new system?