How to repair a corrupted Sata hard drive?

My Sata hard drive recently became corrupted. Before the corruption occurred the graphics were breaking up, the system was occasionally rebooting by itself and there was a general slow down of most processes.
Whilst I was trying to diagnose the problem the PC wouldn't boot up.
I used the XP installation disk a couple of times to fix the master boot record and was able continue using the PC to try and solve the problems.
Finally the system wouldn't boot up even after using the XP installation disk, and an error message was displayed that the NTLDR file was missing
I subsequently found that the system's problems were caused by a faulty motherboard and I've now replaced the motherboard and hard drive.
I now want to try and recover about 20GB of data from the corrupt Sata disk.
I have temporarily attached the corrupted Sata drive to my repaired PC and it shows up in XPs Disk management window as Active and healthy and shows the correct 80GB capacity. However, the corrupt disk does not show up in 'My computer' or in the Phoenix/Award Bios.
Before I try to use recovery software, I was wondering if anything could be done to encourage the disk to show up in My computer, so that I could more easily access and transfer its data. My repaired PC is using a 120GB ATA HD and the corrupt HD is attached to Sata port 1 on the motherboard.
Any suggestions would be appreciated.
My current PC spec is:
XP Pro SP3 + updates. 120GB Seagate Barracuda ATA HD. AMD 2.GHz CPU. 1GB RAM.

Try assigning the drive a drive letter in disk management -- right click on the area that says healthy and select an available drive letter. Should then show up in Windows Explorer.

You will probably need to use some data recovery software then to get anything off the drive.