Recover hard disk data after deleting partitions

When I reinstall Windows XP by mistake I deleted all five partitions. I did not format them yet though.

How can I recover the partitions? When I attach the hard disk to another PC it just says that the partition is unformated and asks "Would you like to format it?".

Solution 1:

Use ralford's suggestion together with TestDisk :

TestDisk is a powerful free data recovery software! It was primarily designed to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally deleting a Partition Table). Partition table recovery using TestDisk is really easy.

Solution 2:

Partition Find and Mount should be able to recover your partitions.