Do a CTRL+ALT+DEL to launch Task Manager. With the internet browser open and you supposedly not doing anything else, click on the Networking tab to see if your internet bandwidth is being used, then click on the Processes tab and click on the CPU column heading to sort descending to see what process is using your CPU. Web search the name of the thing that's using up your CPU to get an idea what it is.
You can also in the Processes tab, click View, Select PID, then on the suspect process, make a note of the PID #. There's a DOS command you can do to get it to list what services are using that process.
This might help you narrow down what is screwing with your computer, then you can decide if you want to disable that or uninstall or whatever.