I have taken a laptop drive and put it an external case. In the hope to retrieve some files (as the laptop has pretty much had it) however it is a partitioned drive, and will only open up drive D, (in 'my computer' it only shows drive D) im trying to open drive C that has the OS installed on this part. I have even tried setting it as the first thing to boot from on my new laptop, but it doesnt pick it up.
Is there any other way i can try to open the other partition up (DRIVE C)?
"How to assign a drive letter
To assign a drive letter to a drive, a partition, or a volume, follow these steps:
1. Log on as Administrator or as a member of the Administrators group.
2. Click Start, click Control Panel, and then click Performance and Maintenance.
Note If you do not see Performance and Maintenance, go to step 3. Performance and Maintenance appears in Control Panel only if you use Category view. If you use Classic view, Performance and Maintenance does not appear.
3. Click Administrative Tools, double-click Computer Management, and then click Disk Management in the left pane.
4. Right-click the drive, the partition, the logical drive, or the volume that you want to assign a drive letter to, and then click Change Drive Letter and Paths.
5. Click Add.
6. Click Assign the following drive letter if it is not already selected, and then either accept the default drive letter or click the drive letter that you want to use.
7. Click OK.
The drive letter is assigned to the drive, to the partition, or to the volume that you specified, and then that drive letter appears in the appropriate drive, partition, or volume in the Disk Management tool."
Since the older drive is now mounted in an external case, its Partitions will be assigned new letter names by your NEW computer that are NOT the same as they were in the old machine. In particular, your new machine will ALWAYS want to use the name C: for its own drive it boots from. Then it will assign later letters to other storage devices and their Partitions.
It seems form your description that you can access one of the Partitions on the old drive under the name D:. In fact, maybe by coincidence that was the letter name it had in the old machine. But for whatever reason it is not assigning a letter name to another Partition on the old drive. That MIGHT be because the old drive has an indicator somewhere that it would prefer to call its first Partition C:, but Windows knows that name is already in use. So use Disk Management to fix this. What is not made clear in the procedure elel quoted is where. In the Disk Management window look at the LOWER RIGHT pane. It scrolls to show all its contents, and each hardware device will be represented by a horizontal block. Your old drive in the external case should be there as one block with sub-blocks. The leftmost will be a simple label block that calls the unit something like "Disk_2", a size, and a couple other things. To its right there are probably two other sub-blocks, each representing one Partition that already exists on the unit. Each Partition will be treated as a separate logical "drive" by Windows. Each should have some info shown like a letter name like D:, the Partition size, its File Type (NTFS or FAT32), and a unit status. My guess is that one block clearly will be the D: drive you can see already, but the other may not have a letter name. You RIGHT-click on that unnamed Partition to get a menu, and one choice is to change to give a name to this Partition. You can only use a letter not already in use. Once done you exit out of Disk Management and reboot the machine so Windows can update its Registry and use the drive properly.
One thing can still cause you a problem. If for whatever reason the File System shown on a Partition is RAW, this means there is a little corrupt data on the drive and you still will not be able to use it. If that is your case, search the web for how to recover from a RAW Format drive. There are processes for fixing the problem so that you can get all your files back.