How to uninstall intel sound card

[Husse]

You uninstall the driver, or possibly blacklist it.
To do that you have to know what sound you have
Post the output of
lspci | grep sound
or
lspci | grep audio
or if that does not give you anything the output of lspci
Then we can help you.
You may find what you found above in Synaptic - if so uninstall it....
However this is built into the kernel in most cases, just as it is built into the motherboard and blacklisting my be needed

[Husse]

How can I go about blacklisting a module?

A really hard question to answer, because you have to know the exact name.
When/if you know that it's simple, you add it to
/etc/modprobe.d/blacklist
This is an example of how you do it
--------
# causes no end of confusion by creating unexpected network interfaces
blacklist eth1394
--------------
Now I saw you have a "ugly" modem. If you turn that off you turn off sound. This is true for this kind of modem/sound and there is usually some kind of switch for that.
And if you don't use the modem it's better turn it off

[Husse]

I think most laptops has a small switch somewhere to turn off the modem
The item to blacklist may be snd-ac97-codec, but that may be to "general" an option