The WEP key should work if nothing has changed. Have you tried connecting the new laptop by ethernet cable first and then try setting it up wirelessly. Obviously you have made absolutely certain that the key has been copied correctly - O instead of 0 for example. The best way to ensure this is to type the key into a word document then copy and paste it when asked for the WEP key.
Sony Vaio Z Canvas release date, price and specs: Another Surface Pro rival but for the US