No matter how crappy the paste may be it never let's the CPU get so hot like that.
You can find paste at most computer stores, before applying clean your heatsink and CPU HIS with Alcohol (The stronger the % the better) Use tissue paper and wipe as much as you can until it's squeaky clean. Then get another piece of tissue and wipe it again and see if there's more coming out, because when it becomes clean, the tissue you wipe with it should stay clean. If it doesn't keep cleaning.
Now take out your paste and apply it on the center of the CPU and it should be the size of an uncooked piece of rice.
Like so :
Then give the heatsink a final wipe and check the feet and make sure they are close to each other as possible so that one doesn't stay out while installing it.
After you put the feet inside the holes of the motherboard, work in a cross, which means, click the top left then the bottom right, and so on...
If you've done everything correctly your CPU shouldn't run as hot as 90 degrees anymore.