in that case your system may be seriously hosed.
Please open an elevated Command Prompt, and run the following commands.
DIR C:\Windows\SFC*.* /S
it will take a minute or two - please post the full results. Here are some instructions to make life easier 1) To open an Elevated Command Prompt Window (the ECP window), click on Start, All Programs, Accessories – then right-click on Command Prompt, and select Run as Administrator. Accept the UAC prompt. 2) To run the commands easier, highlight the block of commands, and right-click on the highlight – select Copy. In the CP Window, click on the black/white icon at top left – select Paste. The commands will run but may not complete the last command, so hit the Enter Key once. 3) To copy the results... click on the Black/White icon in the top left, and select Edit... 'Select All', and hit the Enter key - then use Ctrl+V or r-click+Paste to paste it into your response.