1. The registry consists of two basic components: i. Key ii. Value
Keys are used to organize the values (and shown only in the left pane). Values contain the actual information stored in the Registry (and shown only in the right pane). There are quite a few different types of values that can be stored in the registry, but the most common that you will see are String (REG_SZ), DWORD (REG_DWORD) and Binary (REG_BINARY). String values are indicated by the "ab" icon and store strings that can represent elements such as names, filenames, paths, and types.

For example, in the Uninstall\CCleaner subkey, you will find the following:
DisplayName Cantains a REG_SZ value that holds the string “CCleaner (remove only)”
UninstallString Contains a REG_SZ value that holds the string "C:\Program Files\CCleaner\uninst.exe"

When you select CCleaner in the Add/Remove Programs tool, the program in the UninstallString entry is executed, performing the uninstallation.

2. Each subkey under uninstall subkey represents a specific program. Many of the installed programs registry entries will show with their names but many others will show with a key label such as:

{333BECA0-DED8-4139-A516-8D9E44E22669}

To determine which program that each key represents, click the key, and then view the DisplayName, UninstallString values in the details pane on the right.

If the program is not listed in the Windows Add/Remove Programs feature of Control Panel and there is no uninstall support included in the program, there still is a relatively simple way to remove the program. However you should contact and ask the author how first.

Macromedia Flash Player installer doesn’t provide uninstaller that’s why it is not listed in Add/Remove Programs.