Read only authority on ext HDD

I have reciently tried to access and change some files/folders on an external HDD that used to be on my old Windows maching, but I have only got read authority. I have tried and failed to find out how to change it to full read/write authority.

Any ideas how I can do this please?

Its an NTFS formatted windows disk, you will only ever have read privileges, unless.....

You install Parragon, a commercial NTFS enabler
Paragon NTFS for Mac OS X software

Or use the open source MacFuse (free but without support)
macfuse - The Easiest and Fastest Way to Create File Systems for Mac OS X - Google Project Hosting

They will allow OSX to write to NTFS disks

Sorry that I haven't replied to this post earlier, but I didn't get an e-mail to say there had been a reply? I think that the easiest way around it is to format it to Mac friendly. I have copies of the contents so not too much of a problem..

I hadn't realised the situation with the NTFS format and Macs. Thank you for the info.