There is a small, simple utility called clip, which takes whatever is given on it’s input stream and places it on the Windows clipboard. There are many useful things this can be used for. Here are a couple of things that save a lot of time and work for me.
1) Add the clipboard to your Sendto menu. Make a command file, like clipboard.cmd, that has this command in it.
clip < %1
Then create a shortcut to this command file in %userprofile%\sendto. Then you can right click on a file and send it to your clipboard.
2) Generate passwords to your clipboard. I use wapg by Adel I. Mirzazhanov (http://www.adel.nursat.kz/apg/download.shtml) by running a command file like this:
set /p PWSIZE="Enter size of password to generate: "
wapg -M SCNL -E"?!|" -n1 -a1 -m%PWSIZE% -x%PWSIZE% | clip
Just think about all the things that you can pipe to your clipboard!
If you are using XP, you will have to copy clip.exe from a Windows 2003 server (%windir%/system32) to your machine.
I would like to mention that using a clipboard extension program will also let you see what you are about to paste. Ditto will even let you edit it right there before pasting it.