Download 7-zip from this website: https://www.7-zip.org/

You can try other softwares but this one just worked for me.

Find The "Serious Sam 2" and right click on it. Then left click the properties.
A window will appear. Click the "Local Files", then go into the game files by clicking "Browse"
Look for the file "Patch_02_090_591918.gro".
Right click the compressed file and open it via the 7-zip.
After opening the archive, locate the "Patch_02_090_591918.gro/Content/SeriousSam2/Music/"
path. Then simply left click the "Menu.ogg" file and press "Delete" on keyboard, after that confirm it
by pressing "Enter" on keyboard or clicking "Ok" by mouse.

You can alternatively replace the music by your own choice.

Thanks for reading my guide.