Beeping through speakers when downloading

When downloading a beep comes from my speakers about every 5 - 8 seconds. Other than this system seems to be operating normally
This is what I have done so far;
1. Downloaded and installed latest drivers for sound card
2. Cleaned all heat sinks
3. Removed CPU heatsink and renewed paste
4. Removed video card and cleaned terminals
5. Removed all RAM and cleaned terminals
6. Removed and ensured security of all drive and dvd connections
7. Disabled all Firefox extensions and addons one at a time.
8. Uninstalled Firefox and clean installed latest version
9. Uninstalled/reinstalled all high definition sound card drivers one at a time

All this and still no joy. Ok all the specialists out there, please help an older bloke who is reasonably aware fix this annoying challenge

Hi all, Thanks for those who looked at my challenge. Eureka I've found it!!!! The situation was that I had checked a box in my internet download checker app and hadn't realized the implications of doing it. I unchecked the box and viola, no beep I can listen to youtube ect without the annoying beep.

Thanks for this post -- but I don't know if that's my problem. First, how do I "uncheck" that box you were talking about? Also, my beep comes thru the speakers about every 50 seconds, so I don't know if it's the samething.

Relatedly, I have a USB driver that I'm still trying to set up properly for my Windows 7/64bit Dell. It's an Apogee Mini Me, and while I was able to download an ASIO driver that works, I'm still trying to configure it for audio recording.

From a far less savvy computer user,

Thanks!