As you removed Avast, we can't really help you with troubleshooting.
I've just re-installed it around an hour ago.
Running Avast Internet Security latest stable build.
Is it still slow..!?
Yes until the avast tray icon loads. As soon at it has loaded, the performance becomes normal.
The next time the computer starts, I will have a better look at Task Manager and see if I can spot anything.