Install not working. Live is OK

Five years ago I bought a Chinese CNC (3040Z-DQ) and play a lot using LinuxCNC on a Dell Optiplex SX270. Works fine.
Then I stopped using it.
I want now to do some work with my CNC.
I've downloaded the last version (2.7 Wheezy).
First issue, the size greater than a CD, my PC not supporting a DVD...
Using an USB memory I was able to boot with the LIVE. Well, no problem, all is OK.
I wanted to install it on the HDD.
The procedure is failing, for some unclear reason in regards to the VESA definition...
A message, which is not well displayed (very tiny size) is requiring either to abort or to give some number.
It's illisible and unclear but related to the display.
Question :
1 - seems curious that the HW is OK for a live usage but not for an install. Any idea?
2 - could I have an idea of what magic number must be given in order to continue the install?

Thank you,

s it still the Dell Optiplex SX270

then you may go direct to the USPACE DVD setup
www.linuxcnc.org/testing-stretch-rtpreempt/

All is OK now.
Thank You

Yes - It is always this old computer - constraint of the parallel port of my driver

A parport PCI Card is at 10USD
so it is no need to keep the old stuff

Agreed.

It's also a question of the size and location of the devices.
The CNC is installed in a dedicated environment (my personal workshop) and the PC is close to this machinery far away from my office.
I have a choice between three computers having a parallel port. All are of the same generation (~2004)
- an old desktop (big tower...) still able of running an XP
- the Optiplex, which is OK now
- a laptop, Aspire 1350 which is probably the better solution: tiny and powerful enough.

I've tried to install the same ISO than for the Optiplex (i86).
Failed.
I will retry now and if you have an idea, I'll be happy.

Best regards
Marc

there are cheep Military PC for Frontline Use
as of the Desert storm opperation availabel

this will hold the dust and ofcause can take alot of hits

you may try to get one of thiem

I was with an internet connexion.