You can if you have made the alteration in your Power Options in Advanced to shut down your computer by pressing the button for about 5 seconds on your computer. That won't help your problem though. Run some spyware programs to make sure it isn't anything like that first.
If not try and clear your files in I/E and I mean all offline files as well.
If all fails after that try clicking Start/run typing in msconfig, when the box opens close disable all services. That will not let you close down the essential ones your computer needs as you will see if you scroll down. Reboot your computer. You will get warning messages to restart in normal mode but ignore that. Once your desktop is in view click start again type in msconfig and this time start up in normal mode. You could also look at your start-up programs in msconfig as well, to see if there is anything in there that you don't need to start. You can even close one at a time until you find the culprit that is causing you the problem.