1. Click start or press the windows key. 2. Search
p;pdata% and double click Roaming. 3. Find .minecraft and double click it. 4. Find Bin and Double click it. 5. Find minecraft/minecraft.jar and click it once then right click it and open with WinRAR or 7-ZIP. 6. Drag the mod file into minecraft.jar opened in WinRAR/7-ZIP. 7. DELETE META-INF. 8. Your done.
(Start> Search
p;pdata%> Double click Roaming> Double click .minecraft> Double click Bin> Open minecraft.jar with WinRAR/7-ZIP> Drag mod files into minecraft.jar open in WinRAR/7-ZIP> Delete META-INF> Done)
If you get a black-screen when playing minecraft go to the login screen and go to options and select "force update".
ITs P;PDATA% and then click on .Minecraft
What if there is no bin file present? A search on YouTube finds that a lot of others are having this same issue.