Laptop getting Critical System Errors

I'm really not sure whats going on. I accidentally downloaded this program called "Gold Codec" and since then I have been getting these popups in the lower right hand corner next to where the time is saying I have critical system errors or another one will pop up and say trogan found. I went to add remove programs and removed the "Gold Codec" program however when i go to program files the folder is still there when I try to delete the folder it says I can't because other programs are using some of the things in that program so I then go into the task manager and end the processes of what files are being used from the "Gold Codec" folder but they go away and keep opening back up in the task manager. I'm really not sure whats going on I would really appreciate any help thats offered. Thanks in advance.