Sound and MIDI playback devices

Well here's another computer dummy with a problem. I
lost everything from my windows xp and had to reinstall
all over again from Dell disks. Now I have no sound and
I get the error message, No MIDI playback device
installed. I've read, read and reread the dell manual
and can't find any simple explanation or any info on how
to find the device or how to install the device and
drivers to get my sound back. The Dell manual for
Windows XP Home is excellent but this subject is not to
be found. I'm totally computer illerate when it comes to
drivers and devices. Can someone help me please before I
tear my hair out over this. I have CallWave and need my
sound back asap.
Waiting for an answer.
Annmarie
P.S.
Thanks