Go in for Diskeeper09. Its completely automatic and runs in real time. Has some awesome features like low free space defrag, free space consolidation etc. Get the trial version and check it out.
The allowable size for attachments varies from one mail provider to another. Hotmail has a 10mb limit, GMX. com allows 50mb attachments.
If referring to Windows Live Movie maker:Click the videofile once to highlight it.Go to the Edit menu at the top.To the very left you see Video Volume.Click it and drag the bar to the left.If referring to the older versions of Movie Maker(like 2.6):Ctrl+U