>>>If I buy Office 2010 off the web, will it access my files and documents created with my previous package which has been wiped?
It should be fine.
However I've no idea why you're thinking of paying for any Microsoft Office product anyway. These are all free (and just as good):
https://www.openoffice.org/
All of those office suites should be able to open (and edit) documents created in Microsoft Office 10. I use OpenOffice, which has no problem handling files created in Microsoft programs. If you choose to use it though, I recommend changing the default 'Save' option. (By default, OpenOffice saves files in its own format. You can use 'Save As' to choose a Microsoft format but it's better to change the default setting so that simply using 'Save' does it automatically):
http://helpdeskgeek.com/office-tips/set-openof%EF%AC%81ce-org-to-save-in-microsoft-of%EF%AC%81ce-format-by-default/
Thanks Bueno. I had a look at your recmendation, but I am such a traditionalist - probably my age - that I prefer docs to look like they have always looked.
I have been using PC's since they were available, and old habits die hard, but thanks very much for your kind advice.