Hi guys I am a new member and this is my first post on toms hardware. Now let me come to the problem that I am currently facing.
Recently, I decided to open my cabinet (this was my first time opening cabinet) and clean all the dust inside using paint brush for delicate components(processor,ram,mother board,fan,etc.) and toothbrush for everything else, the whole process was a success and i was able to take out most of the dust in fact after reconnecting my CPU (as in the whole box) i noticed that my boot up took fairly less amount of time. Then I tried reconnecting my mouse and flash drive through the front USB ports and i noticed that my PC was unable to detect them. Then, I tried connecting them to the back USB ports and it worked.
Conclusion : My front USB ports have stopped working. I have a USB Cable to charge my phone which is short and it is difficult to connect it to back ports and use my phone at the same time.
During your cleaning process, you probably pulled out the front panel usb headers. It's very easy to fix this, reopen the case and look for the black cable that says USB 2.0 or 3.0 depending on what you have, and plug it back into the motherboard. (You might need the instruction manual or online instruction maunal from you Mobo manufacturer.