Hi,
I installed another SATA drive so I can back up my vital data. After hooking it all up, I booted up and checked in my BIOS. It's there and set as the slave. It comes up when I check my hardware, and in hardware monitor..so why not my computer?

I've not installed any OS onto it as I didn't think this was needed..but I'm not expert so any advice in getting it up and running would be great. Thanks

have you looked in disk management?Have you formatted it to slave?Oh and hello and welcome to PC Help Forum.

Here have a read of these links they should help.
Seagate Technology - How To Install and Troubleshoot Serial ATA (SATA) Hard Drives

Seagate Technology - Serial ATA Jumpers and Cabling

Seagate Technology - Serial ATA (SATA) Troubleshooter

Hey Jelly,
I've read both those links, the install guide I've followed to the letter and it still doesn't appear. It does however appear in my BIOS as a slave to my master harddrive. When I check the HDDs properties through Device Manager all the volumes for the disk are blank which I take as Windows not knowing it's there?

I've just checked disk management and the second harddrive does appear, but says it's unallocated. How would I go about allocating it to a slave role? My BIOS sees it as a slave already so now I really am confused

Edit:The HDD shows up in disk management but it's unallocated. Do I need to make a primary partion and slap an OS onto the HDD in order to use it for back ups?

You need to partition and format the unallocated space.

Chapter 2: Prepare the Disk for Windows Disk Protection

The above link may help.