Two steps to speedup your computer.

How to speed up your computer:

Go to Start-Run-When the little windows comes up type;
msconfig
the system configuration utility window will come up and look for the Start up tab and click on it.
Click on the disable all tab.
You will see that all the little squares have their checks off.
Look for the antivirus startup item and click on it so it is checked again. Click apply and OK and restart your computer.
When the computer restarts another window will come up telling you that you have done some changes to your system. Click on the little square on the left lower corner to tell the computer not to show that window again.

Another way to clean your computer:

Go to my computer
Right click on the C drive
Click on properties when the window appears click on Disk Cleanup.
Select all that you want to clean as Old Compressed Files, Office setup Files, Temp Files.
Click OK, and OK again and it will take a bit if you have a lot of trash there.