Which specifc Reader version you have installed on your machine? Also, is the problem specific to one particular PDF file, or all files? It will also help if you can post one sample PDF test file in which you are encountering this problem.
Using the select tool, can you select any of the text you are searching for? If not, it's probably a scan so just a picture of text.
Thanx for the reply - Using Adobe Reader 9 Ver 9.4.3
Sorry; how do I go by posting a file to this forum?