Erasing a "failed" HDD



I have a 40GB hard drive that has failed. I am able to log on for a while before everything freezes and then crashes. I am hoping that the manufacturers will replace it. I do not want them to see the information on it and so would like to do a complete erase. I have had up till now 20-30mins before the system siezes. Is there any way of doing a wipe if I cannot run a CD (it's a laptop, no floppy) for any time longer than that?