<<...can i connect the usb cable from the external drive to my new computer and access my files and use them like i could with my old computer...>>
Sure. An external drive is just a storage drive, can be attached to any system with proper connection...files will be readable, as long as they are not encrypted.
<<...also, the restore software that cam with the seagate is for windows xp or earlier can this be used with the new one,...>>
That's a question for Seagate, provider of the software/drive, to answer.
<<...if not how do i access or restore the files from the external drive?>>
Same comment as question immediately above.
Win 7 also has XP compatibility mode, Win 7 and XP Compatibility Mode