Just to expand on what was discussed last night with a few links for those interested
1) format is used to clean out your drive , as you use it then your drive and registry gets clogged up and slow so a periodic clean up and start again helps , for info on partitioning and formatting see here
http://www.theeldergeek.com/hard_drives.htm
http://www.theeldergeek.com/f.htm
REMEMBER WHEN YOU FORMAT YOU LOOSE EVERYTHING SO TAKE A BACKUP FIRST
2) nero ( or other back up utilities) are insurance for when things go wrong. they take a mirror image of your drive( complete with any errors) , you can store this image on a seperate partition, second drive or cd/dvd.