Two options here. Buy a bigger hard drive, fdisk it, partition it, format it and install it as a slave to your original disk. Copy all your files across to the new hard disk and then clean up the original without deleting the operating system. or option 2. get a boot disk from click here and install the new hard disk as the master (disconnect the original for now) make sure the BIOS detects it and also that your pc is set to boot from floppy disk first. Now use the bootdisk to fdisk, partition and format the new disk. When that is done reinstall the original as master and the new as slave. Get a copy of xxclone from click here and copy your complete old disk to the new (bigger) one. When that's finished, take the old one out make the new one the master and reboot. When you are happy everything is working OK you can, if you want, reformat the old one and have it as a spare or install it back as a slave for storage.