There's a program called designworks Lite, which you can download a shareware
version of.
It's has a rather strange interface which takes some getting used to but it's
dedicated to schematic diagramining.
You can copy / paste straight into word, but this of course increases
document size quite rapidly. A better method is to copy into a paint program
and then convert to jpeg or a similar smaller-sized picture format.

Alternatively, I have a very VERY simple to use Windows CAD package called
EASYCAD which you can save your drawings as WMF's or DXF's. Either of these
formats can be imported into Word.

>32M of RAM is also a good idea !.

Regards,
Darren