Ok. Did you try updating your drivers? Sometimes, if there is an error in the drivers, or if something gets corrupted, your computer will not communicate with the devices properly. I just ran into this problem with my client this week.
If you update them, and the problem still persists, we can walk through some additional troubleshooting methods.
Go to www.driveragent.com
. It is free to scan your computer but it costs $30 a year to be a member. I love the site because you can have unlimited driver updates and downloads. You will not have to search for them all over the net. the scan tells you which drivers are good and bad and which ones need to be updated. This is an awesome tool to use, especially when you are pressed for time fixing a client's computer.