Need advice - poor sound quality on my computer/Youtube

Hey, thanks in advance for any help with this. First, I have an old Emachines computer, 8-9 yo... My problem is this, whenever I play streaming music from internet radio stations or most any source other than youtube, it sounds fine except for some short cut-outs if I'm surfing the internet at the same time. With Youtube it sounds like the music is coming out of a washing machine about 50% of the time. I know in general much of the music on youtube will not be of the highest quality, but that aint the problem. It just tends to come out all warbly. I have high speed cable internet and just can't figure out the problem. It started about a year ago. Any ideas?

 

Thanks for the advice... I know I'm way overdue for a new computer. Just don't understand why one or multiple other music streaming sources would work fine but youtube does not. Thanks again.

 

Thanks, I'll give this a try before trashing everything and starting anew.