I'm guessing you were using OpenOffice with Ubuntu. If so, download OpenOffice for Windows here: http://download.openoffice.org/
Then convert your documents to .xls or .doc so you can open it in Office 2007.
That sounds likely to me too. As an alternative to downloading and installing OpenOffice on your Windows 7 system, you could also just go back to the original documents on your Ubuntu system, re-save them in MS Office format, and re-copy them to your Windows 7 system.