Unable to install freebsd

[Claude Fournier]

I want to learn more about freebsd and consequently I have purchased a new motherboard SYNTAX, DURON AMD integrated video card, sound and ethernet.  The computer has 256 MB of memory, an old western digital 6 GiG hard disk and a CDROM 40X.  I burned the ISO image of 4.8 and 4.9 release and ran the SYSINSTALL.  I can only go as far as : (1) unable to swap to /dev/ad0s1b and (2) unable to make new root file system on /dev/ad0s1a.  Needless to say, I can not run freebsd.  I created on big slice, actually the whole hard disk, and partition according to instructions selecting the auto option.  Is there more information I could get on how to get around this issue.
Thank you.