My house has 2 wire romex and just 2 prong outlets and I want to switch the outlets to 3 prong will there be any fire hazards or shock hazards if I don't have the bare ground wire

Yes there is a shock hazard missing the equipment grounding conductor.

You may use either a GFI circuit breaker, or a GFI receptacle, and label each outlet 3 wire receptacle that has no ground "No Equipment Ground".

The GFI device will protect from shock hazards.

As long as all is wired and installed properly, fire hazard is not an issue.

Thank you very much. Does the GFI have to be the first recepitcle in the circuit or can it be anywhere in the line. The reason I'm asking one of my lines runs 2 bedrooms upstairs and 1 bedroom downstairs. It could take awhile to find the first outlet.

Yes , A GFI receptacle needs to be the first in a circuit to be able protect the remaining circuit, or use a GFI circuit breaker.