Hello there,
I am a Linux newbie and I decided to install Slackware 12.0 on my (rather old) computer (Aspire m1610). Therefore, I used a USB key in which I put Slackware's ISO with Unetbootin. I created three partitions on sda (that seems to be my hard drive, fdisk does not acknowledge hda). The setup program was working rather well until when I had to select from where to install Slackware (source media selection). Indeed, it proposes me to choose either CD/DVD, hard drive partition, NFS or pre-mounted directory. Of course, I want to install it from my USB stick... So what must I choose ?
Furthermore, I have troubles finding my USB key in /dev/ since I cannot mount anything in that directory. I tried to create a "usb" directory in /mnt/ and to mount something (e.g. hda or sdd) but it says it is an invalid device.
Thanks in advance.

Why 12.0? I used to have a laptop (it died) with similar specs, and it ran 14.2 OK while it lived. And might have run 15.0 (32-bit). With a later release you might get the USB option.

Before running setup, you can manually mount slackware usb, assuming it is /dev/sdb1

Then you can choose "pre-mounted directory" and then feed it /slac/slackware64 as the path (just slackware if installing 32bit) -- specs say aspire m1610 came with 64-bit version of windows vista, so it is 64-bit compatible. Just because it is old hardware doesn't mean newer versions of linux won't work; although, modules that run older devices sometimes are removed from the generic kernel to keep it trim; it can always be rebuilt with those modules still present.

Regardless of slackware version, usually setup detects its own install media... but if it did not, manually mounting the usb key should rectify that situation.

Thank you for replying,
The device sdbX does not exist.
This is the content of /dev/:

Update:
I finally mounted my USB stick. Then, I installed Slackware from my mounted directory. The setup went wonderfully except that the installation of LILO failed.
After that, I tried to boot from my hard disk but... there isn't any OS in it.
(I mounted sda and it seemed valid)

why slackware 12 and not 15?
It maybe /dev/hdb?

More likely the stick is sda with the hard drive as hda. istr that usb devices were treated as scsi in the days when that distinction was still being made. And that /dev directory with all those devices looks like a static one to me, which would mean a pre-udev kernel.

I actually thought that it was better to choose an older version of Slackware since I have an old hardware.

What year does the Aspire m1610 date from? I'm running Slackware64 15.0 on old hardware: Thinkpads X200 (2008?) & T410 (2010?), and a Dell Precision T3600 (2012?), all bought refurbished. Try 15.0.

With a trimmed down desktop environment, like xfce, (and without java), slackware-15 is snappy on old hardware... installing java makes starting X11 and some applications slower, but once it's loaded and cached it's snappy again...

If you can do everything you want with what already comes with slackware, then whichever works; but if you use lots of 3rd party packages, the qts, pythons, and other various libraries have had so many revisions since what was included in 12.2, that the developers and package maintainers have moved on, such that there is generally less support than with the latest stable version...