HIS Radeon HD 6670 after processor overheat

Now, my graphic card's fan is at a constant 39%, when idle or gaming.
It seems to play games worse now, after my CPU overheated and my computer froze.

For example, I was playing Need for Speed World on Maximum settings at around 30FPS. Then my entire computer froze, and I had to shut it down by holding the power button for a few seconds. When I tried to start it back up, nothing appeared on the screen. My father took a look at it, and he said my processor overheated. So he cooled it down by removing it (I think) and got it working again. But now, the GPU fan speed is constantly 39%, and it plays games worse now. Need for Speed World at Max settings now plays at about 16 FPS.

I need Professional help.

If computer froze, it probably crashed, if crashed maybe some software or settings got changed. Usually hardware works or it doesn't. Now, if you took CPU out and put it back without applying paste or it is not properly seated, that could keep it running hot and throttling back.
As far as GPU goes, if it runs slower then there is less heat, then fan won't go above idle which it seems that 39% is.
You should run some programs to check temp, frequency and other stats for CPU/GPU to find where the problem is first.

Got it.

Check system configuration and see how many cores are set. Natively windows, on multicore cpu's defaults to one. System configuration, boot, advanced options then check the box and then click the arrow for the drop down menu then select the highest number.

Nope, didn't work. But my computer seems to be going faster. I'll enjoy that

Just to make it clear, which part is the problem? Is it the GPU itself, the CPU, or even the motherboard?

Re apply the Thermal paste with Arctic Cooling MX 2 on your CPU & GPU after cleaning the heatsink & the processor/ GPU Chip.

Apply in very little quantity in the middle of the chip. Make sure you don't apply it like butter.

Re seat the heatsink & connect the heat sink fan. Power up your system & You should see lesser temps than the one above.

I did the same for my Gateway Netbook.

The temperature dropped from 60 degrees to 34 C in Idle.

Now it maxes out at 54 degrees.

I'm really sorry about the late response.....
I'm not sure that I can do what you said. I'm not THAT old, you know.
I still live with my parents, and I get nervous when I ask them about my computer.
My dad is AMAZING at computers, so its really intimidating to ask him about that stuff.
Maybe the next time he goes to New York (about once every 1-2 months)