Why is my computer making this noise



I tried to change the sound device but then it still continued to happen. Restarting my computer again seemed to fix the problem. But what worries me is that I changed around some settings with the registry by using TCP Optimizer right before restarting... I doubt it was TCP Optimizer though.
 


.............then uninstal TCP Optimizer ....

and if you have a backup of your pc......restor it.....