To ensure the authenticity of a document you have to sign the document with the certificate. I will show you how you can easily sign PDF document with the help of simple tool DigiSigner.
If you leave your computer running on a 24/7 basis you might be interested in determining the amount of uptime that has accumulated since the last reboot.
By default the command line outputs are displayed onto a screen, but you can easily redirect into a text file or even make it to be used as an input for the following command.
Windows 7 have a nifty feature which combines the windows of opened applications under the same taskbar button. If you don't like it you can always turn it off.
If you put your computer into hibernation, the next time you turn it on, you'll get all your windows and programs open just the way they were before the shutdown.