PCs cannot open my Macword docs

When you are done, do a "Save As..." from the file menu, and then you can save it as a different Word format that you should be able to open at work.

are you using office 2008 at home and 2004 at work?
if so, 2008 uses .docx and the older office uses .doc ext.
with the mac - select save as 2004-2007 format and you should be good 2 go on the PC.

I do not have other save as options. I use Microsoft Word: X. My only save option in SAVE AS: "Microsoft word document"

What version of Word do you have? There should be a drop down menu in the "Save As" dialog box that has different formats to save as.

I have Microsoft Word X for Mac version 1983-2001 The save as options for word that I have are
Save as: Microsoft word document, word 4.0 for mac, word 5.0 for mac and word 5.1 for mac. The other save options are templates, webpage, stationary, text only etc. no other word save options.

does your document has the ".doc" / ".xls" ending visible?
pc's need to see that...