sorry you are having problems. here is what i think is going on...
msn weather works (as far as i know) but hasn't been used in rainlendar for quite a while. you must have a version that is almost a year old or more on your first computer. the newest stable version of rainlendar uses the google weather api. the weather gadget now only requires you to input your city (or zip, can't remember). that is probably what you have loaded on your 2nd notebook and why you can't use the same msn weather link. HOWEVER, last week google shut down their weather api so the most recent version of rainlendar's weather widget will not work either. Rainy has since made an alternate weather widget using yahoo weather. he has said that the next version of rainlendar will use a proper yahoo weather widget but in the mean time just to use the alternate version. here is the link:
hope this helps.