I downloaded a bad file now I'm in trouble (MacBook)

[flipper_mcgee]

I don't know what's going on. I'm a new user. On my first search, the results were overloaded with spam. I clicked on one, and downloaded an .exe file.

Ever since then, the computer has been really slow.

At first I thought the slowness was the result of having downloaded Limewire, or that the use of Limewire caused other functions to be slower.

But, I quit Limewire and the problem has continued.

I have a new MacBook and I was told that it was not susceptible to viruses.

Well, something is wrong, and I need help and advice to fix this, it's driving me crazy. Can someone advise me on how to solve this? Do I need to take the computer to a computer shop?