If your Microsoft Windows Sidebar disappears or stops working on your desktop, it may be because of Software changes or a poorly built-in gadget on your computer. If you want to restore your windows sidebar on your desktop, you can follow the given steps:
If you want to change Windows startup programs, then follow this blog-How to Change Programs at Windows Startup
Step1: Click the "Start" button and select "All Programs".
Step2: Click Accessories->right-click Command Prompt -> select Run as administrator. Type your password and give the confirmation.
Step3: In the Command Prompt window, type:
Regsvr32 atl.dll -> press Enter
Regsvr32 "%ProgramFiles%\Windows Sidebar\sbdrop.dll -> press Enter
Regsvr32 "%ProgramFiles%\Windows Sidebar\wlsrvc.dll ->press Enter
exit -> press Enter
Step4: After exiting the Command Prompt window, restart your computer. And check that windows sidebar is working properly or not.Find here, the best way to enhance your system performance.