Lost the Word program on my PC, have a weird one now?

We had a virus on my PC and ended up having to get it all wiped out, including the programs. I used to Have a Word program on it and for writing I used to switch between the PC and my Notebook lap top which has Microsoft Office Word 2007. But now my PC has some weird Open Office program (blue icon with 2 birds) which can open my Word files but cannot save the changes to them - they have to be saved as new documents. When I go to open these new documents in my lap top, Word can't open them without turning all the characters into gibberish. I need to install Microsoft office word onto my PC but can't find it in stores to buy. Shopping on the internet for computer stuff is terrifying to me, especially after losing everything to a virus despite supposed firewalls and virus protection (Norton sucks). If anyone knows where I can just buy a friggin disc with Microsoft Office Word 2007 on it, it would be awesome - I rather just pay a hundred bucks for it in a store than get another virus downloading from some shady site on the internet. Thanks.