carsick

Hello. I've had hard drives go down on me before and thought I lost another one recently. I've been burned too many times so I want a complete mirror or RAID 1 setup (I do have backups, but this is also my business PC so can't afford to be down that long).

My PC:

new MSI K9A2 Platinum
320 Seagate sata drive
Vista Home Premium
2 gig 800mhz RAM
AMD 5200+ dual core
A second Seagate identical 320gig hard drive

Questions:
1. Does the second hard drive need to be blank, or will it just simply be written over?
2. Does the information on the existing drive remain on the drive or does it get deleted during this process?
3. Do I need additional hardware?
4. Do I need additional software?
5. What is the sequence of steps from a hardware and software installation standpoint?
6. Is there a tutorial/link on the actual install process that I can look at first?
7. Any other info I should know before proceeding?

As you can tell, I'm a novice at this building stuff. If you decide to reply, please try to dumb it down-way down. Thanks in advance for your reply.