Try reinstalling windows, select 'upgrade' on the installation screen to avoid losing any data. If that doesnt fix it then check the bios settings, if the devices are all listed. then it is possible your hard drive is failing.
I have windows XP and for some reason I cannot get out of safemode setting. I have run check disk and it did not fix it. I have no sound. I have check the device manager it shows no hardware.
Any help is appreciated.