vanishing HD

[cbf]

I had 2HDs on my machine 1 vista 1 XP not dual boot but independent selecting from boot option in bios.
When I replaced my MB with a Gigabyte X38 both my drives were unbootable and repair would not work. Any ideas?
I then added another HD and re-loaded everything. Now every so often my computer locks or reboots. In the bios my new HD (c:) is missing can only returns when turning computer off and on. A reboot does not find it.
Please advise

 

[cube_]

First, how are all 3 of your drives connected?

Second, you need to reset your CMOS settings man.
Don't proceed here yet; tell me your hard drive connections first.

Turn your PC off and unplug it from the wall outlet. Next, open your case up and look for the small round silver CMOS battery (looks like this).
Gently pull it out and wait for about 15 seconds. Place it back in and start up your PC. This should have reset your CMOS settings and hopefully now detect your new and old drives.

 

[cbf]

Hello,
I have 1 ide drive and 3 sata. It is my new sata C: drive that keeps getting "lost"

Thanks

 

[cube_]

So you have 4 drives in total?
1 ide and 3 sata? 1 on which is a new sata drive?

Previously you said you had 2 drives