KS --
I assume you are seeing a schedule conflict warning in the Planning Wizard
dialog. If this is not your situation, then you definitely need to
elaborate more about your problem.
Assuming you are seeing the schedule conflict warning in the Planning Wizard
dialog, then this means your schedule has slipped past an inflexible
constraint, such as a Finish No Later Than constraint. So, first, look in
the Gantt Chart view for any task that has a FNLT constraint, or any other
type of inflexible constraint, such as Must Start On (MSO) or Must Finish On
(MFO). After you locate those tasks, jot down their names and/or ID
numbers. Then, click View - Table - Schedule and pull the split bar to the
right to expose the Total Slack column. In the Total Slack column, look for
tasks that have a NEGATIVE value. You will probably see a chain of tasks
with negative slack. The last one in the chain is probably the one on which
you have the schedule conflict. To resolve the schedule conflict, you would
need to remove the constraint, or you need to replan the predecessor tasks
so that you do not slip past that constraint date. Hope this helps.