usb problem

I simply can't figure this one out.

MsP has an old Dell Optiplex 270 desktop, one day (a while ag0) we found all 6 usb ports stopped working.

Updated drivers etc .... have been working on this problem for sometime

'All" being out seems to tell me this is not a hardware problem but I can't find a software solution

MsP now has a laptop so its not a big deal but I just want to find the solution

according to the device manager nothing is wrong, no yellow ! or ?