My basement lights, dishwasher and tv on ground floor keep going out all at once. The breakers are all ok. trying to find out what else went out I turn on my electric stove and all come back on. This has happened 4 times sense I had my air conditioner fixed.
Details based on typical USA 120/240 service.
Sounds like you one of your phases is out. Residential power typically comes in 2 phases. If everything is set up well then you have ~ 1/2 your receptacles, lighting and other single-phase circuits (120V) on one phase and the rest on the other phase. A few larger appliances - e.g., oven, electric water heater, air conditioner - will use BOTH phases.
If one phase goes out then everything on the OTHER phase will still work. However, if you turn on an appliance that connects to both phases then it can backfeed from the good phase to the bad phase. This can cause all sorts of problems.
Unless you have had work done on your electrical system recently that might explain it (in which case, call the electrician who was doing the work), this is most likely an electric company problem. Call the electric company, tell them you think a phase is out. If they don't respond with "we'll be right over to check it out" then make sure they know that you are concerned about a life & death safety issue.
I missed the first time around that you had your Air Conditioner Fixed recently. That should not CAUSE this problem, but it could be related, and could be the cause. So check first with whoever did that work (HVAC tech. or electrician). If they are clueless, call the power company.
Until this is resolved, the safest thing to do is to NOT use any 240V equipment - Air Conditioner, Oven, etc. If you have an electric water heater then that may be part of the mess - any time it cycles ON you would have backfeed power, and when it cycles off you would "lose" power - except if you turn the oven on.
If you do have an electric water heater, I recommend turning it off during a "everything seems OK even though the oven is off" moment and see if you "lose" power again.
Definitely get a professional to check it out immediately.
This is a "red alert" situation.. well, OK, "Yellow alert". There's a related but slightly different problem that is "red alert" because it'll fry all your appliances and start a fire. This may only fry motor motors e.g. your A/C unit.
But the power company should come out quick and look at this for free. They may end up chasing it to a problem on your side. In which case you'll need to bring out an electrician; it's not practicable to get from skill level of "replacing the occasional outlet" to "servicing main feeder" overnight.
If any recent work was done, that might have something to do with it, but that's no guarantee.