how can i save a .txt file in C:\? I keep on getting a permission box preventing me from doing so.

The short answer is that you shouldn't save files to C:. This is the root of the Windows system partition and is thus under UAC. If you really must (and you really shouldn't) then you can

Right-click on **C:**
Select **Properties**
Select *Security** tab
Click **Edit**

in the Permissions for C: window

Select **Users(computer\Users)**
Select **Modify** and **Write** under the **Allow** column
Click **Apply**

UAC will ask for authorization