These instructions are for Windows Vista. Show Windows 7 instructions
Because Adobe does not provide a 64-bit plugin for their Flash player, gadgets that require Flash (such as Pandora) will not operate on 64-bit Windows. To get around this problem, you can run the 32-bit version of the program that manages the gadgets. Here's how:
This is the easiest way, and the one I recommend. Adobe has recently begun offering a beta Flash player for 64-bit browsers. To get it, visit its download page and download the "active-x plugin for 64-bit Windows — for Internet Explorer only". After installing it, exit Windows Sidebar, then start it again.
64-bit Windows comes with a 32-bit version of sidebar.exe, the program that manages the gadgets. You can set this one to run on startup instead of the default 64-bit one.
Recently, someone pointed me to a post on The Average Gamer detailing how to automatically launch the 32-bit Sidebar instead of the 64-bit one automatically every time you log in. Here's how to do it: