You know How old is your computer?
You just need to do the following:
1 - Click on Start
2 - Click on Run
3 - then type the following command::
DEBUG
-click on OK.
4 - The cursor will move to a new line.
5 - then type the following without leaving any space:
df000:fff5
6 - Then press ENTER
7 - and you will see the production Date of BIOS.