Hi All,

I am having G580 series Lenovo laptop and it is already having Win7 OS.
I want to have dual boot OS on my laptop. The HDD is of 500 GB and of that i am using 200 GB in windows and rest 300 GB is free space.Now whenever i am trying to install ubuntu 10.04 LTS or Fedora 17 on this laptop, i am getting error as "not enough space on disk". I am not able to understand when there is already 300 GB free space, then why i am not install Linux OS on this system.Please provide me some directions on partitioning.

Regards,
Ravi

It needs to be unallocated space - not free space within a NTFS partition. Post a link to an image from device manager in Win7 to show us how the disk is configured.

Thanks for your reply.Attached the snapshot for your reference.

Attached Thumbnails

 

And that's the other possibility I almost mentioned. The classic partition layout only allows 4 (maximum) primary partitions - even in Windows.
One of those 4 you have has to be deleted and the resulting space then allocated as an extended partition - it's a special form of primary partition that allows sub-allocation of logical partitions within it. See Wikipedia for a general overview of the structure. Linux can be installed entirely in logical partitions.
In your case best would be to delete the OEM (probably tools like a media player, or maybe a recovery partition). Be aware of what functionality you might lose, and ensure you have Windows backups that you can restore a full system from first.

My first thought would be to leave the recovery partition as is and copy the D drive data to the c drive or external since it is only ~2GB. Delete D and then create an extended partition that includes the 210 unallocated space. The d drive can then be recreated if desired.

If something happens the OP can reload windows back to "out of the box"