Sorry, I should have responded to this in my first reply. Linux/Ubuntu is a lot different than Windows. The underlying file structure is different, and the way Ubuntu (and other Linux GUI's) present the desktop is different. Frankly, it takes some getting used to, but once familiar, is easy to navigate.
As with anything else, a little time invested in playing around with it will be rewarded.
You state you now have a PC with Linux/Ubuntu installed. Is this a new PC? Is this the only operating system on the PC? If so, you may be able to configure a dual boot situation where Windows can reside on the PC with Linux (you'd have to partition the hard drive, adding a Fat32 or NTFS partition for Windows). Once that's done, Linux will recognize that partition but Windows will not recognize the Linux partition.
Mine is a dual boot configuration. I can use Open Office (on Ubuntu) to run/create Microsoft Office documents and store them on my NTFS partition. I can also run some Windows applications because I have Virtual Box installed.
Sounds like the configuration I've got now. My hard drive crashed - I was running Windows XP. When I got my notebook back, I did the dual boot thing and mostly use Ubuntu and occasionally boot into Windows XP for a few specific things. I'll have to try Virtual Box to see if I can boot if I can boot into XP even less.
Talk about understatement.