First thing to realize: One-year warranty on system, motherboard is standard.
2d thing: Onboard solutions for video, sound, USB, modem, etc...are provided as an accomodation by motherboard makers. In the past...and, for some of us, in the present...PCI cards provided these functions.
3d thing: Anything manmade can go bad, especially if it's outside the warranty period.
USB 2.0 controller cards eliminate a lot of potential grief and are what I consider to be inexpensive. Easily installed. Example follows: http://www.newegg.com/Product/Product.aspx...N82E16815106505
Now...if you removed the device, using Device Manager...rebooted and then allowed the device to be reinstalled...and you still have no joy, my guess is that the onboard chip for USB is just not doing the job and probably won't be able to do so in the future.
If a part will solve a problem for me and costs less than $10, I don't even think about it...I just get online and order
. I have it within 3/4 days with no special shipping and it resolves an irritating situation.