Problem:
Suddenly, after detached and re-attached  a WSS 3.0 content database , the WSS 3.0 search service or Search Server 2008 Express (SS2008E) cannot crawl the portal anymore.
So i began to refresh the service and repopulate the search index by performing these  steps:

Redefined Alternate Address Mapping (AAM)
Reset all  Search Server 2008 Express crawled content
Restarting the WSS [...]