My gaming pc is very good but the other day the cover came undone.
So I decided to take it off and put it back on but i was in the dark. I accidently stuck my finger in cpu fan and now one of the blades broke. So it started to buzz now i started a game and it lock up is the fan not working no the cpu temp will go up to 100 degrees.
Yes, chances are it's not working. You're computer will usually shut off if the motherboard doesn't think the CPU heatsink fan is running, but maybe because you just broke a blade, the fan still runs, but not effectively, hence the buzzing. I would stop trying to run your computer at all until you can replace the fan. The good news is that it's just the fan from the heatsink so you can buy a new fan and attach it to the heatsink and plug it into the motherboard and you should be up and running in no time. Fans usually aren't to expensive. Check online and make sure you get one with the right measurements (usually in mm).
Make sure you replace the fan. And also check if you might have knocked the heatsink. Make sure it's still connected and makes full contact with your processor chip.
I hope this helps!! Good luck!
A new fan or new heatsink (with fan) will solve your problem. Don't operate until you repair/replace. You may damage your CPU or the mobo (particularly the capacitors located near the CPU socket) from the heat generated. Not a major deal to take care of this problem , but can get expensive if you don't. Good luck!