Usually booting in safemode on a PC means tapping f8 as soon as you power up, and keep tapping it. You'll see a menu with the start in safemode option. Use cursor keys and return to select. On a laptop it maybe f2 but whatever you have (it might all be different now) just keep an eye on the screen when you turn it on (blink and you'll miss it) it'll normally say in the corner of the screen.
Once you're in safemode, (I suspect where WyeDyed is going with this, but since he's out for a bit) standby for further instructions!