To Boot into safe mode here is what you have to do. Feel free to print these directions below.
1. Shut off your computer
2. Turn on your computer and start pressing the F8 key every second. You should see a similar screen to the below image. If Windows Starts to load that means you missed it and will have to try again.
You will see several options. The option you want is Safe Mode or Safe Mode with Networking
Safe Mode: Just starts the basic Windows OS with out many drivers and other support options
Safe Mode with Networking: Same as above but the "with Networking" option will allow you to go online and download programs. XP users may need to still turn on their wireless device in the Netowrking options to connect.
What is the Purpose of Safe Mode?
Safemode is normally used to help resolve issues you are having and to trouble shoot errors. While in safe mode many programs will not autostart as well as hardware drivers. You will notice that your screen may be bigger as well or look a little funky. This is because the driver for this device is not running. While in safe mode you may find it easier to run virus removal programs and remove virus threats.