I Have The Whisper Cyclonic Upright Vac; How Do I Check Belt?

Hoover Whisper Cyclonic Upright U5184-900 vac - great!! Rivals my Dysons (ex took in divorce) but I can't open to check belt on beater bar; light comes on as if it's working, and I've cleaned all hair, string, etc. out of it, and it starts to turn about a 1/4 rotation then stops when I turn it on...this was a gift, second hand, so no manual or way to figure it out. Can't afford new belt to was going to rig something if it's broken, but can't find out where to start without lots of research I haven't time for now. Computer doesn't download really well so manual is wasted and it's slow as molasses now (can't afford virus check). Can anyone just give me a quickie answer until I have resources to do it right? And thanks for your patience, if someone has enuf to do this....