I think I deleted my Wi-Fi?

I have a Lenovo B5045 laptop. When I set it up, there was a load of 'desktop junk' basically, pointless looking apps and programs and it was really slow. So I unistalled a lot of things. Since I have done that, I have not been able to get Wi-Fi on my laptop. There's not a Wi-Fi option either, when I try to connect to the internet it only says 'connect ethernet cable'. I'm posting this off another laptop, but I do have an ethernet cable if I need that.
How can I fix this?
Thanks! I know I mustve been really careless and stupid…
also if this is in the wrong thread can you tell me where it should be posted?