Well it sounds suspicious, that there may be a problem with that outlet, such as neutral gouging. If you are not familiar with electronics, then you will need an electrician to check it.
Now these modern receivers have a lot of complex microprocessor circuits. These circuits do need stable power.
I think these sophisticated HT systems are not adequately served by surge protectors. Now I know I have disagreement about this, but I stand by this advice. These new complex systems need an online UPS to drive them. Low voltage and glitches are just as serious as surges. America's grid is deteriorating fast along with the rest of our crumbling infra structure.
These units are cost effective. Pick one that has enough power, to power your system including the TV. You will still need to have your outlet checked and preferably have your electrician put it on a dedicated circuit.
http://www.refurbups.com/Catalog/Smart-UPS-Rack