I downloaded Adobe Photoshop CS2, the 30 day free trial. Everything worked fine until I...(pls read on)...?

I opened the program. Nothing works because there was this box that popped out and said that I wasn't allowed to continue because my account does not have the proper privileges, and that I should log in using an account with administrator privileges. My laptop is Windows Vista, and I was told before that I can change my account settings by going to the control panel>user accounts. But it doesn't work!!! :'( Can anyone please help? I need this Photoshop real bad. :< I didn't buy the PS cd since I have all the codes with me.