Not to mention that in Norway the VAT is included in the price, whereas in the U.S. the Sales Tax needs to be added on top. For a fairer comparison, you would actually need to add the appropriate sales tax for your state. That wont make up all of the the 25% difference but could easily add 7 to 9% to the cost of the U.S. price.
Keep in mind though VAT is very different to sales tax. If it's a b2b purchase you will almost always get VAT refunded on the purchase by the government, which afiak never happens in the US on sales tax. So it is actually cheaper in the EU/EEA to get a laptop as a business (as you will reclaim the VAT in Europe but you wouldn't be able to reclaim the sales tax in the US).