@Rosangeles It won't get hot enough to cook macaroni, but as Fassou points out, it looks like a textbook throttling.
If you don't have the budget for a new machine, take it to a very reliable service center and have it properly maintained.
While you're at it, have the HDD replaced with an SSD of at least 128 GB, and if the replaced HDD is in good health, put it in an external USB enclosure for extra storage.
The total cost of the operation will be much less and you'll significantly improve performance.