After formatting and installin win 7, selecting OS option for Ubuntu not available at booting

Omgubuntu has a guide named " sticking it to grub " the Windows installer has overwritten Grub on the MBR. You can put it back using the chroot from live CD / USB.

To be on the safe side you should have made the backup of your Ubuntu BEFORE the computer guy started installing Windows 7.

If he has chosen to install Windows using the whole disk, then all former Ubuntu data are already gone. Only when he has selected to re-use the Windows XP part of the hard disk for Windows 7, and to leave the Ubuntu partitions intact, then you have the chance to access your old Ubuntu data.

For checking whether the Ubuntu partitions are still available on your hard disk, you have to inspect the disk layout of your system; this should work with any OS

Either boot Windows and start disk management; how many (and what kind of) partitions are shown there?
Or boot into an Ubuntu live system (from DVD or bootable USB stick) and use gparted or partitionmanager or fdisk to list the partitions; how many (and what kind of) partitions are shown there?

Thank you Action and Manfred. Actually the guy said he has kept the Ubuntu data intact and said that he will remove the hard disk from my laptop and use some machine to get my data back, but I really dont wanto to tamper with my laptop. So I will create a Ubuntu USB stick and then ask for further help after reading the guide Action mentioned.
Thank you once again.
Mak.

Hi,
this is what disk management showed me. In windows Ihave C and D drives. So the first unnamed might be Ubuntu. And could it be that windows cannot read it thats why its saying 100 % free?
regards
Mak

https://imagizer.imageshack.us/v2/1051x631q90/636/d16527.png

Windows is not able to read ext2/3/4 file systems. This might be the explanation that it (without any better knowledge) calls it 100% free.

It seems you should try booting into an Ubuntu live system and check the disk contents there.