вызываю справку, пишет: no topic based help system installed.
переустановка дельфи не помогла. что делать?

"The problem is caused by the installation of the VS2005 Beta which resets some AppID-GUUID. Afterwards delphi crashes while loading the IDE-package htmlhelp290 which in the end causes delphi to think that there's no help installed

I fixed it doing the following:

Reset the help-viewer-appid. In the registry under HKEY_CLASSES_ROOT\AppID\DExplore.exe, set AppId to {4A79114D-19E4-11d3-B86B-00C04F79F802}
In HKEY_CURRENT_USER\Software\Borland\BDS\3.0\Disabled IDE Packages remove the entry for htmlhelp290 that has been created.
Start Delphi and use the help again "

http://www.gnegg.ch/archives/250-No-topic-based-help-system-installed.html