I was helping a friend replace outlets in his old house. The original outlets have two wires and no ground. They are mounted in a metal box. We installed the new 3 pronge outlets and used grounding pigtails to ground them to the metal box. We turned the power back on after completion and none have power. We flipped all the breakers being we were not sure which breaker powered that room(we killed the Main when we did the work). Any ideas why no of the outlets work or switch in the room works?

Sounds like you have 2 problems, Lack of power could be at the first receptacle in line, Verifying power out of all breakers would be a good thing. When you get power going, see if you have voltage between the hot(small slot in the recepticle)and the ground, if not it may be romex. If you see voltage between the hot and ground, it may have been run with conduit, which is good and would be your ground.

We still need to find the fisrt receptacle in line and see if it has power. We ran out of time yesterday. Thanks for the point on verifying the power on the breakers. I guess my other question is would adding those pitails cause the issue?

No, the grounding would not affect the power at the outlet.

First check you work. Most likely you have two or more cables in each box. All of the wires must be connected together and connected to the outlet. That is, all the blacks connected together and all the whites connected together. This can be done by connecting the wires to the outlet directly if you have only two wires, or by connecting the wires together using a wire nut and using a pig tail to connect to the outlet. Most likely you either missed a wire or disturbed a connection under a wire nut.

The electric code says that when replacing ungrounded outlets with grounded outlets they must be GFI protected. Connecting a ground wire to a metal box does not necessarily ground the outlet. If the box is not grounded the outlet is not grounded. Because ungrounded outlets were used does not necessarily mean that there is no ground wire in the cable. Look at the cable to see if there is a ground wire. If there is, most likely it will come out of the cable, bend and go out the box through the cable clamp. In other words the original installer would have bent the ground wire back and wrapped it around the cable and put the cable in the box. If it's there you can see it. If it is there, loosen the cable clamp, grasp the wire with a pair of needle nose a pliers and try to pull in into the box. Some times you get it all, some times it breaks. Depends on how tight it is wrapped around the cable. Most of the time you need to add some wire to have enough. You also need to connect all of the ground wires in the box together and add a pig tail to connect to the outlet.

If you do not have a ground wire in the cable or cannot get it, you need to use GFI outlets. You can replace each outlet with a GFI or you can replace the first outlet with a GFI and wire it properly to protect all of the outlets down stream.

Thanks. I checked each plug we replaced with tester on the wires themselves and they read no power. This kind of makes me think it's the breaker. Thanks for all the advice.

Highly unlikely to be the fault of the breaker. Reset each breaker by turning it off then back on. If the breaker immediately trips again you have a direct connection between the hot and the neutral some where. If the breaker resets, start pulling outlets and check for voltage between the black and white wire of each cable.