If I under the problem correctly, You're unable to open Photoshop as it is asking you a password to open it. Right?
You need to have the administrative rights of the owner's user account if there is any such restriction to prevent others from using apps installed under his account. Also, Which version of Photoshop are you using? Here are instructions to run Photoshop as an administrator Running Photoshop As An Administrator (Windows) – Code & Hustle Support
Let us know if that helps.
I am using a seperate PC, how do i sign in as admin and able to use it on a seperate computer?
it keeps saying sign in and when i sign in it says my subscription is not recogized
Are you signing in with the Adobe ID and password the account owner uses?
No, but i am added to his user list?
try sign in with my adobe id and password as it is registered with his account as a user.
The other users subscription licenses his Adobe ID, not the software. So if you are logging in and do not have an active subscription it wont allow you use until you subscribe.