Peter, I have just checked Sibelius 7 First Sounds Downloader under Windows 7 and it works fine (here in the UK).
Please check the following, and then answer the questions at the end:
1. When you click the download link in your account at shop.avid.com, within your web browser you should choose to "download and save to hard disk" (select a known folder on hard disk to which to save it), and do NOT choose "Run" from within the web browser. Do NOT use any download accelerator product.
2. When the download-and-save is complete, open the known folder in Windows Explorer/Mac OS Finder. There should be a file there named (in the Windows case):
(where 99999 is a sequence of digits), and it should be 2294 kBytes in size.
In the Mac OS case it will be called
and it should be about 7300 kBytes in size. This is a standard Mac OS disk image file. Double-click to mount the disk and open it.
3. Under Windows: double-click that .exe file. It will require your agreement to elevate to Administrator status. A dialogue panel entitled "Avid Downloader" should open. First it will explain to you that it is going to install Pando Media Booster, and ask you to agree to that, then it will install Pando Media Booster: this will take only a few minutes.
4. Then it will ask you to nominate another location to which to download the large Sounds installation files proper. Configure that as you wish - the default is your desktop folder.
5. Then it will start the big download (using Pando Media Booster): the panel will say "Downloading Sibelius 7 First Sounds Windows Installer", with a progress bar. This stage can take many hours, depending on your broadband connection speed.
6. A folder will be created at the location you specified in step 4 called "S7F Sounds Installer - RC". During the download, this folder will be filled with various files.
7. When Pando Media Booster finishes the download, the "Avid Downloader" panel closes and is replaced by "Sibelius 7 First Sounds Installer" Welcome. You then follow instructions to install the sounds.
8. Once step 6 has finished normally, if step 7 fails, or you want to repeat step 7, you do not need to download anything again. Just navigate to the "S7F Sounds Installer - RC" folder and open it.
8a. On Windows, inside "S7F Sounds Installer - RC", open the "Windows Installer" folder. Inside that, double-click to launch "Sibelius7FirstSoundsInstaller.exe" to perform step 7 again.
8b. On Mac, inside "S7F Sounds Installer - RC", double-click to launch "Sibelius 7 First Sounds Installer"
If you have problems with the Pando Media Booster phase, there is a help file at:
Those users who report "No internet connectivity detected": please say exactly at which numbered stage in the above sequence that message appears. A screen-shot of the message might be helpful.
Sibelius 7.1.3/6.2/5.2.5, PhotoScore Ult 7.0.2, Dolet 6 for Sibelius, Windows 7 32-bit SP1, 4GB RAM