HDD Not in Win7 but in BIOS

For the past week one of my 1TB storage drives has been picked up in windows during boot but disappeared shortly afterwards but would come back when I rebooted. Since installing this week's WIn 7 updates the drive no longer shows in Windows at all.

I have repaired the machine and restored it to an earlier point pre-update, I have changed the SATA cables and port it is plugged into but no joy in Windows yet it always shows up fine in my BIOS.

The HDD disappeared the same time I experienced boot crashes and started to get the long startup times that other members are posting about.

I have also made sure all my drivers are up to date though there was one instance after changing the SATA port that the system said it failed to install a driver but it didn't tell me for what device.

Any help in how I can get it back without formatting it? It has a lot of information I don't want to lose. Its also not a boot drive if that makes a difference.

Sounds like it could be a failing HD. That is the standard reason for not being able to see it.
Have you tried
sfc /scannow
(There's a space between sfc and /scannow.)
You could try the repair function on the Windows 7 installation disk, but this is primarily directed to repairing your OS, and I am assuming from your post that the problem is not there?

One suggestion to save you data. You could try and autoboot with one of the many free live CDs, which can be downloaded from the web, and see if that can connect to the HD. You are then in a good situation to copy over you private data.

I've just tried sfc /scannow and it came back clear but the volume doesn't show in CMD either.

Would you be able to recommend a website where I can get a live CD from? Do these boot straight into a program or would it be a command prompt and I'd have to manually copy things over?

My apologies for the late reply. I have only just noticed your response. Try this:
http://www.livecd.com/