Losing modules

[Jan and Bertil Smark Nilsson]

Greetings,

I've just installed Fedora Core 4. Apart from Grub being very slow when 
booting up and not being able to boot Windows 98SE, which I've solved by 
producing a bootup CD, when I try to activate the speaker typing "depmod 
pcspkr", I lose the function of several modules, such as sound, network 
and the ability to access vfat. Needless to say the the PC speaker hasn't 
been activated.

Any ideas?

Bertil