From your description, I understand we are failed to find the related registry key about silverlight. If there has been any misunderstanding, please let me know.
After my research, I find that our issue may occur by the cause that the installation files was unable to be extracted properly or there is some service conflicting with Silverlight Installation process.
Based on the current situation, I suggest we perform my suggestion to narrow down the cause of the issue and fix it.
Step 1: Clean Boot
=============
Let's disable all startup items and third party services when booting. This method will help us determine if this issue is caused by a loading program or service. Please perform the following steps:
1. Click "Start", go to "Run", and type "msconfig" (without the quotation marks) in the open box to start the System Configuration Utility.
2. Click the "Services" tab, check the "Hide All Microsoft Services" box and click "Disable All" (if it is not gray).
3. Click the "Startup" tab, click "Disable All" and click "OK".
4. Click "OK" to restart your computer to Selective Startup environment.
5. When the "System Configuration Utility" window appears, please check the "Don't show this message or launch the System Configuration Utility when Windows starts" box and click OK.
6. Check whether or not the issue still appears in this environment.
Note: Temporarily disabling the Startup Group only prevents the startup programs from loading at startup. This shouldn't affect the system or other programs. We may still manually run these programs later.
Then please refer the following steps to install it again.
Step 2: Use the Winrar to extract the program
===================
Before doing the installation, Please access
Get Silverlight | Microsoft Silverlight
Note: I assume that you have saved the Silverlight.2.0.exe file to C:\.
1. Download Winrar tool from the link below.
http://www.rarlab.com/rar/wrar371.exe
Please Note: The third-party product discussed here is manufactured by a company that is independent of Microsoft. We make no warranty, implied or otherwise, regarding this product's performance or reliability.
2. Follow the instructions to install Winrar.
3. Right click Silverlight 2.0.exe, click Extract to Silverlight.2.0\ option. A folder Silverlight.2.0 will be created after completing above steps.
4. Enter this folder, double click silverlight.msi to install.( I had to do a search to find this file)
5. Double click silverlight.msp to install.
After completing above steps, let's check if silverlight can be installed.
I am sorry for any inconvenience you have encountered and please be assured that I will do my best to help us to fix the issue.
Your time and efforts are highly appreciated on this issue.
