I have Windows 7 and have stored my computer for the last 2 months?

Everything worked perfectly when it was shut down in April but now that I have it back, everything is slower and huge (writing and screen) and a box comes up that says toI get the 1280 x 1024 resolution but when I try change it to that, it goes back to 860 x 600. How can I change the resolution? I read on here that I probably need a new video card but I have to know the name of it. Where do I find the video card? Sounds like a silly question but I am not too up on computers. Thanks for any help