gas filter location

i was given a 91 ford tempo, 4 door, 4 cylinder, awd. it needed work, but it runs decently and gets great mileage. my problem is the electric windows. to start off, the front windows worked but were a bit slow at times going up and down. the back windows go down but not up, and make like a clicking sound when you use the buttons on the drivers side. about 2 weeks ago my drivers front window was really sluggish going down and i used my hand to help it go down. now it won't go back up. there's no noise when i push the button, and it's almost like it's getting no juice. the passenger side front window is working great. up and down, and the back windows are still doing their thing, clicking when you try to get them to go back up. i had the fuses checked today and they were fine. if one window is working, and two partially and one not at all, could it be something besides the motor for the windows? and is there just one motor or several? i'd like to get a general idea before i go to a garage. no sense in getting ripped off if i can help it. thanks

I have a 2002 Buick Rendezvous with 25,000 miles. While waiting at a traffic light with low rpm, the dash warning lights come on momentarily and then go off. Specifically, the battery light, seat belt light, and others which I cannot remember. The vehicle has the original battery. I am thinking dying battery or alternator. Are there other ideas?