How do I not seem ungrateful?

My mom got me one of the old Mac book pro’s (A1278) and I’m really thankful she got it for me for college but I’m having so many problems with it. It runs really slow, it takes thing forever to load, it wouldn’t let me record orals for my Spanish class and sometimes it doesn’t load images that I need to see for that’s class, the battery dies extremely quickly.

I’m thinking about just buying a brand new laptop on Black Friday for myself because I’m so frustrated with the one I have. I’ve talked to her about me buying a new one with my own money but she tells me just to have someone try to fix it. I don’t want to seem ungrateful but its not working for me at ALL.

I just don’t know how to tell her again that this isn’t working and I need a new computer without hurting her feelings. I was planning on getting an HP computer or a dell. I rehusar want a laptop that’s fast and will let me do all my college papers.