Win7下C盘无法创建文件解决办法：
To fix it, just turn off the User Account Control (UAC). In Windows 8, do not turn off the UAC via control panel, it must go through the registry.
Press keys “Windows Key + R”, type regedit Locate HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA Update the EnableLUA value to 0 (turn if off) Restart Windows.