I messed around a bit too much with the win xp recovery console (fixboot, fixmbr) and corrupted my partition table. I reinstalled grub and now I can boot, but gparted refuses to see my partitions, but with fdisk I can still see them all though...
I really need to repartition... I have no way to backup the whole hard drive, so a clean setup is no option...

How can I fix my mbr or my partition table, or whatever is the cause of this?

Warning: If your partition table was/is corrupted you may not be able to recover the partitioning. With that said, as a suggestion look at something like the SystemRescueCD and parted to possibly recover your partition table;

http://www.sysresccd.org/Main_Page

parted might be able to recover the partitioning if you know roughly the size and starting locations of the partitions. Hint start at the front (sector 0) and move forward one partition at a time.

I actually don't know what is wrong... fdisk shows the partition table exactly as it was, but gparted seems unable to read it :? I guess it can't be the MBR, because the only thing that should reside in there is grub, right? So what is wrong with gparted? :?

I'm going to print the output of fdisk and use the tool you suggested to 'repair' the partition table... hope it helps...

anyway, thanks a lot in advance to help me out

Get a 2nd opinion and run cfdisk.

fdisk is the last line of defence as it can read corrupted partition tables while other partitioning tools have all given up.

Post the output of "fdisk-l" and all will be revealed. A record of it posted here may save your skin later on because your partition table can suffer damage or loss of information during the rescue attempts.

In general fdisk and cfdisk should be enough for rescuing the partitions.

A complete destruction of the partition table, which is just 64 bytes in the MBR, will not affect the partitions internal data. You can rebuild it and suffer no loss of data. I have done loads of them often to the maximum 63 partitions in a hard disk. The trick is always to keep a record of the partition table.

You can even create a copy of the partition table to save someplace;

# dd if=XYZ of=backup.bin bs=512 count=1

Replace XYZ with actual device name such as /dev/sda or /dev/hda.

Now to restore partition table to disk, all you need to do is use dd command:

# dd if=backup.bin of=XYZ bs=1 count=64 skip=446 seek=446