The power button broke off on my acer tablet and I had it soterd back on and now it won't come on at all how do I get it to come on

Using standard solder can be brittle and the connectors can break quite easily , best solder to use is the softer type , it's possible one of the usually 4 connector types could have cracked and you're not getting a circuit , sometimes if a ribbon button setup is there it is better to replace the whole ribbon with power button than repairing solder however if directly connected to the PCB , sometime you can use a piece of metal or foil to create the circuit by touching one side solder points to the other , this may work but ideally replace the faulty button switch you could attempt soldering the switch to a permanent on position , however this could cause your device to loop on and off