Disk particition is missing

I meet a very strange problem. One of the laptop got two particitions, and for some reason the disk has corrupt files and can’t boot. I connect the disk to another computer and let windows xp to automatically recovery those corrupted files when started.

Then the problem happened: the disk is about 140G and each particion is 70G. From device manager, I can see a “D” drive of 140G, but from windows explorer, the D drive is only 70g! I don’t know how come device manger can recognize the whole disk but only displays one particion. I need to restore some important files from the missing partition.

Any suggestions will be appreciated.