Well basically I was dualbooting Win8 and Ubuntu 13.04. I wanted to try out 13.10. So I booted a life usb and selected the option "Erase Ubuntu 13.04 and Install 13.10". And turns out the new installation erased everything. Any idea if I can recover any of it?
You won't be able to, I'm afraid. It would take a forensic data specialist many hours to image your hard drive with dd then to try to recover the NTFS partition, and the chances of success are slim.