I got a used CPU and I'm worried because it seems to be overclocked. So, I've gone into the BIOS, made sure (to the best of my ability) no OC settings were on, and checked my Target CPU Turbo Speed, which was 3400 MHz, as expected. Everything seemed to be disabled/automated, so I don't know where to go from here. Using Task Manager while I'm playing a game, I can see it stays around 3.74 GHz, but the average TEMPERATURE can reach 80 degrees CELSIUS and at that point I exit the game. Any help would be appreciated. I've already ordered an aftermarket heat sink to help with the temperature problem, but I don't want the clock speed to be over the factory settings.

[attachment deleted by admin to conserve space]Fastest reset for BIOS is to clear it on the main board. As far as 80C I have concerns that your heatsink might not have proper thermal compound on it or is going to be inadequate for it even at the 3.4Ghz native clock. A 10% overclock shouldnt be pushing you into 80C TEMPS.

Did you clean up the CPU and Heatsink surface of OLD thermal compound and add a drop of new thermal compound center of the CPU before adding heatsink? Is the fan spinning ok and not clogged with dust?

Your memory might be set to a 10% overclock that is causing the CPU to run overclocked via faster FSB setting. For example I overclock my Athlon 64 x2 4450B from 2.3 to 2.53 Ghz by a 10% FSB overclock setting from 200 to 220Mhz since my multiplier is locked to 11.5 x 220Mhz = 2530MhzSo, I should reset my BIOS to default settings? There isn't a value I can change somewhere? I don't want to mess anything up.

I cleaned the heatsink of thermal compound and there isn't much dust, but I can remove that too. I've had problems setting my heatsink. I believe 1 or more pins have expanded and they don't fit. 

The first time I set it I was sure all the pins were through. My only problem may have been too much thermal compound and not being able to set it properly (I couldn't get the diagonal pairs to go in at the same time). the second time I kept the motherboard in the case and spread the compound on the heatsink. This didn't seem to make a difference.
Once the new heatsink comes in I'll try again.

I'm not going to lie, I can barely understand that last line. From what I do gather, I don't understand how my RAM could be OC'd. I bought it new, if that wasn't clear. 
Sorry if I went above and beyond your knowledge of computers. The reason why I suggest a BIOS reset is because it would set everything back to default. If you cant locate the reset for teh BIOS you could also select to set the bios back to default in the bios itself which is usually an option. However a manual reset by jumper, push button on main board, or removal of 2032 battery and reinsertion of it is a guaranteed reset back to default.

What do you have for hardware such as CPU, RAM, and Motherboard make/models.

Example of my system specs of system I am currently on:

CPU = Athlon 64 x2 4450B 2.3 Ghz
RAM = 4GB Corsair DDR2 800Mhz XMS2
Motherboard = Biostar MCP6PB M2+I found the reset option in the BIOS, but I wasn't sure what effect it would have on the computer so I decided to not mess with it.

I actually posted my specs in the attachment and added more info about the cpu. I didn't want a bunch of text and I didn't see an option for adding "click to reveal text" so I just threw into an attachment.

Well, I never mentioned it, though. I'll fix that now.
EDIT: well, nevermind, I can't fix it. Here are the basics:
      Operating System: Windows 8.1 Pro 64-bit
      CPU: Intel Core i7 3770 3.40GHz    Ivy Bridge 22nm Technology
      RAM:  8.00GB Dual-Channel DDR3 666MHz (9-9-9-24)     
      Motherboard: ASRock Z75 Pro3 (CPUSocket) 
      Graphics: 2047MB NVIDIA GeForce GTX 960 (EVGA) 
    The i7 3770 will automatically overclock itself up to 3.9GHz if it needs it and is running cool enough to do so, what you are seeing here is standard operation of the CPU from the factory.Thanks Camerongray for info on the auto-overclock for that CPU. I wasnt familiar with that feature of the i7 to automatically overclock itself.

Looks like once he gets his cooling ( damaged heatsink mounts ) resolved he should be all set then in regards to Quote

Using Task Manager while I'm playing a game, I can see it stays around 3.74 GHz, but the average temperature can reach 80 degrees Celsius and at that point I exit the game.