I haven’t heard of baseboard heating before, my guess is that its one of those American terms which we Brits call by another name.
Anyway, I guess they are something like radiators, or at least there is a water distribution system around the house.
Two things spring to mind, one is airlocks, there will be some sort of vent plug in each of the heaters at the top, bleeding the air off may solve your problems.
The next is, how old is the pipework ?It might be that they are blocked by a long accumulation of debris, if you open the vent plug you should get a flow of water out, and at a reasonable pressure.The pipe that will be blocked is nearly alway one that runs parallel to the floor.
If these heaters have individual thermosat valves, these might have seized,and they always seize up closed.
There is another possibility but it would depend on the way the system is connected.
On each heater there is usually an inlet valve and an outlet valve, the inlet one should be fully open but the outlet one has to be set carefully.
If all the outlet valves are fully open then the heaters that present the lowest resistance to fluid flow get hot, and the ones that show the greatest restriction stay cold.
It this is the case then you need to balance your system, first go to any hot heater, and place a thermometer against the inlet, check the temperature and compare this with the outlet temerature, there should be a differance of at least 5[sup]o[/sup]C, but you may need to check manufacturers recommendations.
If the differance is smaller than this it means that the fluid is passing throught the heater too quickly, so you close the outlet valve a half turn, wait and measure again.
Eventually you will get the correct temperature differencial between inlet and outlet, then you move on to the next heater and do the same.
You have to go around every heater but the problem is that a change on one heater affects the system as a whole, which means you need to go round several times.
As a quick check to see if your system is unbalanced do this at the boiler unit first, and if the temperature differance is too small you will then have to go round the heaters.
This information should be there in the boiler handbook if you have it.
As for the electrics, look at the rating stamped or printed on the front of it, it will read something like 10A.
Next go around the house and check how many lghts you have and what power they are, this will be in Watts.
Add up all the light powers and then divide this number by your lighting supply voltage, if it comes close to or exceeds the value of your circuit breaker you may need to install one with a higher rating.
If the circuit breaker is old it may well have been tripped so many times that it operates at too low a current, so it may just be a matter of getting a new one.
IMPORTANT, do not fit a higher rated circuit breaker if you do not know the current rating of your house wiring.
If you are not an electrician then you should call one in.
Look here for some possible anwers to your heating probs
http://www.handymanwire.com/questions/heatingq.html
and here for electrical probs,
http://www.handymanwire.com/electrical.html