How close were you fishing to your buddies? Sounds like you might have been blasted out from the other sonar, which can cause all kinds of issues (including what you were "not" seeing). Especially in that depth of water, you get a few sonar's on the same freq within a few feet of each other there will be some crosstalk.
You should be easily able to see a simple sounding sinker on your line, provided the transducer is level and under the rim of the ice.
If you suspect it's an issue with crosstalk, have your buddies switch to a different IR setting, or you can change yours also by going to the Noise Rejection setting under the sonar menu. You'll have Low/Med/High/Off, and you're probably on Off. Use the lowest you can get away with.
Breaking the "ring" will be difficult, but you're much better off learning the graph mode. It was a pain for me too - but there's so much more information on it. Make sure you're not on "Auto Depth", set the depth manually to the nearest depth (so if you're in 35', set it to 40' manual so you lock the bottom in) and turn on histogram (AR Mode under advanced sonar settings), that'll give you a vertical flasher next to the graph which will help.
There's a learning curve with these types of units, but they are significantly more powerful than the traditional spinning flasher. Once you get the quirks worked out, you'll be amazed at what you can see. Heck the GPS is worth it alone!