Joined: Jan 2008
Posts: 23,639
Likes: 1,106
From: Mans of NC & SW UT Desert
Bikes: 86 Katakura Silk, 87 Prologue X2, 88 Cimarron LE, 1975 Sekai 4000 Professional, 73 Paramount, plus more
+1 Disconnect cable. Move derailleur by hand as far as you can inward and outward. Adjust the stops accordingly so derailleur cannot go into the wheel (spokes), and not outward past the smallest cog. Once they are properly set, you should NOT be touching the limit screws again.
Print out the Park Tool tutorial, it is excellent, and will take you step by step. If the Park Tool tutorial does not make sense to you, I would head to a co-op and get some hands on help.