sounds like there may be some blockage in pipes. try to run a long snake through both drains or run all fixtures in bathroom and try plunging vigorously in tub and shower while running water. if nothing still, it may be possible that your underground plumbing is back graded or incorrect fittings and plumbing installation.
If it stopped working suddenly check the GFCI to see if it tripped. If you think it may be a sediment problem go to a pool and spa store, they have cleaners that can help. In most cases salts won't cause it to stop working.
what you would have to do is this measure how far in to the line you are figure out what wall pipe is in cut access hole to pipe cut pipe and clearout blockage replace pipe your best bet is to go pick up the 3 peices of plumbing first 1. pipe 2.conections
Question edited for correct spelling of maker 'Noen' to 'Moen'.
'Fix' as in it is leaking? Or tighten it down because it is wobbly, or something completely different?
Well, we can have a one on one seminar by the internet. I've been a pumpman for 20 years. I can share with you my experience (household pumps, suibmersible pumps, turbine pumps, gear pumps, piston pumps, dewatering pumps, mud pumps, trash pumps, mining pumps, solids handling pump, etc....) Just take your pick. Just send in your e-mail for assistance. God bless.
Move the lever or turn the knob. Check the stop tap under the sink. Make sure the faucet control knob or lever is tight, There is normally a removable cover that hides the screw..
Question edited for clarity, full 'make model (what it is)'.
This a Menards special. To remove handles, look for a small hole hidden from the front. They take a small Allen Key.