Data recovery after replacing windows with ubuntu

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http://askubuntu.com – I have shifted from windows7 to ubuntu just yesterday. Windows7 was in my 'C' drive. I was thinking if i wipe windows7 and install ubuntu, ubuntu will be installed in 'C' drive only. So I had not take any backup and wipe out windows and install ubuntu. But, ubuntu has formatted my hard drive and i have lossed all my importent data. Now is it possible to recover my data. ....Please help me. (HowTos)