Would you kindly suggest a new laptop for me?

My previous laptop is outdated, slow, and constantly gives me trouble, so I think it is time for a new one. However, I know very little about what laptop makes and models are best these days. That is where you come in, Fluther.

Some parameters:
*I work with photo editing and manipulation alot, so a big screen and compatibility with photoshop is key.

*I need plenty of memory for storage of said photos.

* I need a good, built in wireless card/adapter for my school’s wifi.

* It cannot be a Mac, as my school’s IT is very Mac-unfriendly.

*price range? Under $750, preferably.