Windows7 is a new operating system, and there is less chance for issues. However, if you have lost some features or functions of Windows 7 like Aero, task manager, control panel, no drive, etc either by user intervention or virus attack, here is a solution.
7 Quick Fix is a free, portable tool that can fix 21 common Windows 7 issues with a click. In the past we had covered topics on similar tools (here / here), this one has more options than them.

With 7 Quick Fix you can repair the task manager, windows registry, System restore, folder options, enable or disable IPv6, Aero restore function, enable the command line, no drive issues, display properties, etc.
Download 7 Quick Fix from here (472Kb).