Macro for time stamping..........

Hi,

I have a sheet which updates automatically (It is connected to a software), I want a macro code which show the time at what perticular change is happen.

Example.

In column A and B rates are automatically updated. in column c there is a conditional formating. (if(a1-b1<=0,"sold",""). I when 'sold' appear in column d that time should be written in column d.

I tried with now() but it changes with computer's time.