Audio Driver Down / Dell Cannot Repair / Need Sound

i have a dell inspiron 545s windows 7 home premium from dell.it is a desktop.it is about 2 years old.a few months ago a virus shut my computer down and i paid $275 for the software and software warranty. i also paid an additional $119 for 2 years unlimited technical support. after the technician got my computer up and running again i discovered the the audio for everything (Internet for music and movies) is very low and inaudible and also scrambled. i couldn't fix it myself for weeks so i called dell for help. they checked and discovered the speakers are fine. they told me to pay $59 for a technician to look into it (someone on a website says it's only good for 30 days) and fix the sound system if he could, otherwise i would have to buy a sound card of other hardware and install it myself. my computer which includes the monitor and keyboard and mouse only costs $650. if i shell out anymore i should buy another computer.i like my computer, and i'm trying not to throw anything of the sort into the landfill if i can help it.besides i'm out of a job. do you think i should pay dell any further since that problem only cropped up after they fixed the computer and i wasn't even using the audio when it went down?