How to capture the Current System Year in one Field.

I have two fields:

1. Contact BD:  it is a picklist field with YES and No value.

2. TimeOf Contact: It is a date and time field .

Validation condition : When  user enters NO in Picklist , the date entered in the TimeOf Contact field should not be visible on detail page or it should come blank.

Hi,

   It is urgent .Please Help.

My requirement is:

         I have 4 checkboxes are there in Lead  and also  Percent field. When any of the checkboxes are getting selected the value in the percent field will go on increasing. How to write the validation rule for this one? Please help as soon as possible.

How to capture the Current System Year in one Field.

I have two fields:

1. Contact BD:  it is a picklist field with YES and No value.

2. TimeOf Contact: It is a date and time field .

Validation condition : When  user enters NO in Picklist , the date entered in the TimeOf Contact field should not be visible on detail page or it should come blank.