On a normal Windows boot the operating system loads all the programs and services that are configured to run on system startup. If your machine is haunted by a worm though it might be helpful to boot it with only the basic Windows services running - that is called a Diagnostic boot.
To get going, open a Run prompt by searching for run in the main menu. Enter msconfig. The following window should pop up:
Selective startup should be the one that's ticked. Check Diagnostic startup instead and confirm by clicking OK. To undo the changes, just repeat the steps and check the item that was selected in the beginning.