My blackberry isflashing red but wont turn on

You need to use proper charger to charge blackberries. blackberries wont charge via usb if the battery is empty.

Usually this means the battery is dead. Plug it in to a charger or via usb cable to a computer and allow it to charge for a few minutes, then try turning it on. If you can't turn it on then, let it charge for a while, then unplug it and remove the battery, then put it back in the phone.

If this still doesn't work, go to www.crackberry.com, go to the forums and choose the forum for your particular device model. Have a look through the forum for your device, chances are you'll find your answer there.

Is it fully charged?