Debian etch with 2.6.16.1 RAM not showing up in 'free'

[Prepaid <prepaid@gmail.com>]

Hello all

I have a Debian etch box with a custom complied 2.6.16.1 kernel, running a Tyan motherboard and a Xeon processor (started with Tyan GT20 barebone). Currently there are 4 gigabytes of ram installed on the motherboard, as reported in BIOS, but in Debian the amount of memory shown is the amount for 1 gigabyte.

Ram was originally 1 gigabyte, but then upgraded to 4. but it still shows like it is only 1 gigabyte.
Output of free:
# free
             total       used       free     shared    buffers     cached
Mem:        906232     877028      29204          0      25576     749836
-/+ buffers/cache:     101616     804616
Swap:      1951800      93724    1858076
#

Any ideas?

Thanks