A common problem I have seen in many of the homes I’ve lived in is the occurrence of undergrounded receptacles. These are the two prong outlets that have no grounding option. This means that the house wiring has no way to safely conduct any stray current that escapes the confines of the wire. This type of outlet is grandfathered in to the code laws, but the modern code requires all circuits be grounded.
These types of outlets present minimal danger as long as you do not use an adapter to fit a three prong into a two prong outlet. These adapters can easily destroy the device you are plugging in and increase the chance of electrocution. The only solution in this case is to replace the two prong outlets with modern three prongs but only if the wiring allows.
A major mistake that many homeowners make is to simply swap out an old 2 pronged for a new 3 pronged outlet and assume that will work. A 3 pronged outlet must be connected to a Ground Fault Circuit Interrupter.
The Best option and safest option when dealing with this type of problem is to have a professional come out and ensure that the job is done correctly. Working with high power receptacles can not only endanger your home but also endanger your life. Use a GFCI tester on all outlets in your home after reinstallation to make sure they are grounded.