When you ask a question you need to provide some basic information
-Forum quick start https://forums.adobe.com/docs/DOC-5601
Mac or Windows, and EXACTLY which version of the operating system?
Recent Mac AND Windows operating systems have been known to cause "odd" problems
Are you using a computer Administrator account with full read/write permission?
CS3 and Acrobat 8 activation server is retired see reply #1 https://forums.adobe.com/thread/2372929
-you MUST use the special serial number AND the special installer you download, not your originals
-above includes a link to get the special version AND links to help with activation problems
-more information on activation problems with the new version https://forums.adobe.com/thread/2385900