Sometimes, because of a virus attack some Windows critical features like registry editor, folder option, system restore, right click menu, etc are unavailable and even after removing the viruses these utilities will remain disabled.
Here is a freeware tool called Re-Enable that lets you re-enable all such feature in just with a click.
Re-Enable will let you enable following Windows features:
Windows Registry, Command Line Tool, Windows Task Manager, System Restore, Config, Folder Options, Run command, My Computer, Task Scheduler, Right Click Context menu, Ms-Config (Xp only), Control Panel and Search.
Moreover, this tool also includes a tool menu where you can Scan, Edit, Delete Autorun.inf files, Repair Desktop icons, and reset files and folder attributes.
Re-Enable requires .NET framework 3. Download (for Windows 7, Vista and XP) Re-Enable