Strange installer process takes CPU away

I once tried to download paint onto my Mac computer and then that is when things started getting slow, like I think it became kind of laggy, I ended up going to the task monitor thing and saw that there was a process called installer which was taking up a lot to CPU, I ended it but I decided to test around and hope that I fixed the problem, but I found out that every time I moved something random and useless from downloads into the trash, the process comes back, I didnt really move stuff from the downloads stack thingy until now, but I might of done it once or twice before without any problem, also I think it once started without me even moving anything from downloads to the trash, this is weird, how to I make that stop???

I'm not sure if I explained that right