But what you need to be worried about is the current Sun Brightest Cycle which is reaching it's high level and it is predicted to be 50% stronger than all the other cycles since the records began more than 100 years ago or so. And that will be reached around the year 2013.
That can cause repeated bombardment of the Earth with electromagnetic waves, and booom, no damn computer will work. All fried, Kentucky style if you wish. Just add ketch-up and french fries.
Visit the NASA official website for more info into this.
No cahs registers, no ATM machines, no electronic sparking system in your car, no electronic equipment in planes, trains, and the whole f**g thing.