Problems modifying my own files

I have upgraded to W7 Ultimate. A complete install not an upgrade. I have a second hard drive that has been through a XP and vista period. I have several folders on there that I can't write to adding or deleting. Plenty of other folders that are fine. The root directory is ok too

How do I change this as it is becoming rather annoying

I should include a better description of the problem
When deleting a file i get "you will need to provide administrator permission to delete this folder"

I click the little coloured shield continue button and get "you need permission to perform this action" then underneath "you require permission from (a load of numbers) to make changes to this folder

Works :)