Edit in Datasheet view error

Error:
The List cannot be displayed in Datasheet view for one or more of the following reasons.
1) Datasheet component compatible with Windows SharePoint Service is not installed
2) Your Web browser does not support ActiveX controls
3) Support for ActiveX controls is disabled

OR

A Windows SharePoint Services compatible application could not be found to edit the document.

Check:
1. You dont have Office 2003 Professional or later installed. The ActiveX control required for this feature is installed only during an Office 2003 Professional or later installation.
2. If this feature was working fine before,but now it doesn't. You might have installed some standard edition software ( i.e. Office Project 2003 Standard ) on top of Office 2003 Professional Edition.

Verify:
1. You should have Office 2003 Pro or later installed
2. Your browser does not block the use of ActiveX controls.
3. Check for different versions of Office Program