Free partition recovery software.

It pretty much has most of the the good free/share disk rescue tools available. Been around for ages. Version 12 should be good enough for your purposes. Not sure if thenewest is free anymore but you can always find it in a torrent.

http://www.hiren.info/pages/bootcd

I don't use it myself(I use a live linix CD and dd/ddrescue) but it appears to be well recommended.

Only problem is deciding which of the many tools to use. Research is in order or perhaps somebody here knows.

http://www.bootfromcd.com/compare-solutions/

disclaimer: mostly a Mac user, so I can't recommend/excoriate any of these ...

MiniTools Partition Wizard will recover a deleted partition. Just install it and Click on Partition Recovery on the left. Try Full Disk and Quick scan. When it gives a list of partitions be sure to select ALL the partitions you want including existing ones not just the lost one. You can double click the partitions in the list and it will show the files on the partition before deciding to Apply the changes.
(It also allows you to burn a bootable CD which could be handy if you need to access a HDD in a different machine.)
http://www.partitionwizard.com/help/partition-recovery.html

If you need true data recovery. PowerDataRecovery also from Minitool is slow but good. It doesn't find lost partitions or restore them but goes through the whole disk and finds any files. You then have to copy the files to an external HD or flash drive or different internal HD.
It is no longer free but I could look for the older version on my computer that allowed unlimited copying.

Edit: I think PW is on Hiren's and of course TestDisk would also be on that CD which is another powerful tool but I bit more of a learning curve with that one.

I suscribed just to thank you because Minitools Partition Wizard worked great for me and I wanted to share it. It recovered my lost partitions in seconds. After ran this tool, I still was not able to access to my partitions but I only needed to assign a drive letter for each of them from Windows Disk Manager and ready! Both working again! And best is that Home Edition is freeware. Thank you, guys!

I'm glad PW helped you.

It does often work well for accidentally deleted partitions.

I think a reboot after recovery would have let Windows automatically assign drive letters but thanks for pointing out that manually assigning drive letters might be necessary before the recovered partitions show up in Explorer.