Volunteers are building a database of birth/marriage/death records extracted from the Civil & Parish Registers. The current collection is growing but is by no means complete -the records for many towns have not yet been transcribed. You may search this database at the website of the State Archives in Belgium:

http://arch.arch.be/component/option,com_analyses/Itemid,122...

Note: the search page is in Dutch, though they do plan to have a functional English version in the future. If French is easier for you, you can try here:

http://arch.arch.be/component/option,com_analyses/Itemid,122...

If the people you are searching for lived specifically in West Flanders province, you can try this site:

http://www.vrijwilligersrab.be/page2.asp

It references the same database but you must search by surname within a category (Births or Marriages or Deaths etc.). Results are organized by town, then date.

The State Archives site, by contrast, allows you to modify search terms -to search by first and/or last name, restrict the year range, specify which town, which type of act etc. If your search terms are loose, however, the results will be displayed in no particular order.