If it a laptop then there solider onto the laptop system board. If it a desktop some of them are just wired to the mb and can be replaced. I would check first for bent pins and broken pins on both the devices your plugging in and your pc. If it not a hardware issue it can be a damaged USB driver. Most times updating or installing the mb chipset driver may fix your issue.
Depends on the laptop. Have an Acer Laptop myself, and the two USB ports on the right-hand side of the machine when it's open and facing me are actually connected by a flat ribbon cable. Even if the USB connectors are soldered onto the motherboard, they can be replaced if you are careful and go slowly.