Thanks for the response. Fortunately, I have my installation disc and serial number. Since I have not changed computers, not performed a system reset or registry alteration, and given the fact that I had no problem until the update, I remain at a loss as to the cause. Nor have I added any other program to my computer since the download.
At that time, I logged onto my BigOven, and a prompt asking if I wanted to see if an upgrade was available, and when it said there was, I downloaded that. I exited out of BigOven as per the directions prior to initiating the download, and proceeded as directed. The download did not initially work, and I received another prompt the next time I logged on, and the second time it was downloaded it worked. I didn't try to import any recipes in between the two downloads, so don't know if the problem began with the failed first attempt or the second successful attempt.
Another good reason to keep installation discs.