I'm just getting started with Access 2010 web forms and I'd like to know if there is any way you can into these forms and modify them. What I need is a datasheet with comboboxes added (can be in header section) for searching. Is this possible? How?
Web forms doesn't have design mode - you modify them using Layout view.
If you want a datasheet, I believe you have to create one separately - select the table you want to use as source in nav pane, then on ribbon, choose "Datasheet" - be sure it's for web (easy to tell by ensuring there's a little global icon). You can then add the new datasheet as a subform into another web form.