Thanks to reply #3.

TestDisk is a very useful utility, which is on a Knoppix LiveCD I happened to have lying around. I tried it once and it wouldn't detect my SATA hard drive, but then I realised you need to do it in a root window.

I can now see all my old paritions and all my old files (using testdisk), so I chose to write the partition table.

I wrote the partition table and it now looks like the following:

Code:
Partition                            Start     End     Size in Sectors
1 * HPFS - NTFS        5 0 1 14179    254 63 227721375
2 E extended LBA 14180 0 1 19040    254 63 7809965
3 P FAT32 LBA     19041 0 1 19451    254 63 6602715  [DellRestore]
5 L HPFS - NTFS  14180 1 1 19040    254 63 78091902 [Backup]

* = primarey bootable
P = Primary
L = Logical
E = Extended
D = Deleted
Now when I try to restart windows, I get the following message:
Code:
Windows could not start because the following file is missing or corrupt:
<Windows root>\system32\hal.dll
If I look at the computer using the Windows XP boot CD, it now thinks I have a C:, E: and F: drive.

Before all of this happened, I had just one visible C: drive, so I guess the other partitions need to be merged into this, or made invisible somehow? Once I've done that, I'm hoping that I can use the Windows XP repair install option to replace all my missing files etc and start again...

So my question is, what do I need to do to all that partition stuff?