You will be able to recover the data for free using one of the tools in the previous link, just try a few of the free ones until you find one that works.
Once you have got your data off safely, you can simply go to XP Disk Management as described earlier, then delete the partition, re-install it and the hard drive will then work perfectly. THere is nothing wrong with the hardware, the boot sector code just got corrupted, that's all.