Need to reformat hard drive and restore Time Machine backup. What's the safest way to proceed?
I have a Mac desktop, purchased in 2007. We upgraded last year to Snow Leopard. It has been slow for a few days, and yesterday wouldn't go past the gray screen. Tried booting in recovery with no success, same for safe mode. Even tried fsck -fy. Eventually went to the Snow Leopard install disk and tried to repair disk, but got an "Disk Utility can't repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files" message. I've got Time Machine back ups on an external hard drive, but I want to make sure I do this right and don't make things worse. What steps do I need to take?
Mac OS X (10.6.3)