Over the past few days I've been noticing an unpleasant squealing noise mostly when I start up the car ('89 240.) After a few minutes it would go away, though it took much longer to go away yesterday. At any rate, this morning on my way to work I hear what sounded like rocks being thrown up under my car and a nasty rumbling noise underneath. (The road, however, was completely clear.) After a few yards it went away, but the squealing came back. I was almost to work so I just continued on. Once in the parking lot, I opened the hood and found a fan belt wrapped around the blade of the fan. This belt seems to be the belt in back of the other belts. (The belt to the alternator seems to be there, as does the belt to the A/C and power steering. There is also another belt that seems to go to the fan and it is in the front of this belt.) What is this belt (that broke) called? Also, if I replace this belt should I also replace the other belts at the same time? Once it is replace is the squealing likely to go away or is there possibly something else that could be causing that? Does anyone have a good picture of all the different belts (in position) or know of a good website that does? I don't have a good Volvo repair book yet (but it looks like I'm going to need to get one.)

Thanks for the help.