Following up on the problem and solution: I had tried most of the normal fixes (removing and reinstalling, etc.) and nothing worked. However I went into the forum attached to the link InlandAZ kindly posted and found another person who had problems with Adobe after contracting the AVG 2011 virus sweep scam. That poor person went through endless instructions from Adobe for diagnosing the problem until the end result was that the virus had altered a registry file. Fortunately Adobe had created a kill-bit that once downloaded fixed the problem immediately. Hooray! Hope nobody else suffers this problem, but if you do, follow the link to the forum and get the kill-bit that corrects it.