How to selectively lock few cells to prevent further editing of its content on data entry

Hi,
I had posted this thread earlier in the general section. I am posting it here again as I feel this involves some degree of programming.

I would like to know if its possible to selectively lock certain cells in a row based on entry of specific data in one cell?

Example, I have data to be entered from Columns A to H,
In Row 1, Col A= auto enters today's date and time (I use Now() function), the moment some data entry is made in Col B.
Text or numeral data are entered in Col C - E.
Upon entry of any data in Col E and moving out of that cell, I would like to have the cells from A - E of Row1 to be locked, but should keep Row 1 Col F-H and further open for additional data entry.

I may enter data in Col F - H on some other day or even same day at a different time.

In Row 1, Col H= again auto enters date and time using Now() function, the moment some data entry is made in Col G.
Col F contains some drop down list data.
Here again upon entry of data in Col G resulting in date entry in Col H; these cells should also get locked, allowing further data entry only in Row-2

The problem I face while using Now() function is, when I open the file on some other date, all the dates changes to current date, which should not happen.

Can this be done? If so I would appreciate if someone could help me in this regard.

all help extended to this regard will be immensely appreciated.

thanks in advance.
Regards
Daavis

Hi,
Just modifying my previously posted query along with an .xls file attachment for your perusal.

My need as per the attached file, is :

In Col B-G (Yellow background), in Row 2, the moment data is populated in Col F, Col G gets auto filled (using Now() function); the cells and its data in Row 2 Col B to G should get locked and prevented from further unauthorized modification.

Next, in Row 2, based on the selection from the drop down list in Col-H, Col I (If ColH = Completed) or Col J-L (if ColH=Outsourced)gets auto filled. Then Row 2 Col H to L data should also get locked and prevented from further unauthorised modification.

If this sequence is possible, then I can extend the code to include Cols M to O.

Can someone help me or suggest me how to go about it?

Currently I am using Now() function and the problem is each time the file is opened, the date and time gets updated to the current date and time.

I need this to monitor the status of the test requested for patients coming to our lab.

Any help extended to this regard will be immensely appreciated.

Regards
Daavis.