Well my opinion only if I may, Google the relevant OS and follow the instructions to disable Microsoft updated. The only thing you need to update is your antivirus database. Secondly Google System Configuration if your Run command is enabled type in msconfig Find the tab "Services" and see what is running and Google the ones you think is dodgy and disable accordingly. Always do your homework when doing this. There is also a Boot tab again Google is your friend so have a look what you can disable safely.

Also find a good spyware removal program and do a scan… also do a virus scan…

You will find that your computer WILL run faster.

A last tip would be, press the start button go to your "computer" click on it, right click on your hard drive select properties.

Then click on the tools tab. click on "Defragment now" button. Then click on Defragment disk let it run...

If your PC is still slow start uninstalling the programs you don’t use… Also Google the programs you do use and see how to disable there updates. Some programs can be excessive.