The truth is that I cannot even start the installation. The live CD is loading and all of a sudden it is ejected and this message pops up: unmount: /run/lock/: not mounted
It's an AVERATEC laptop and has a 1.50 Ghz Intel Pentium M processor and 504 Mb RAM.
The disk should be just fine, since I've already done the installation with it (it's Lubuntu 11.10 desktop i386). The checksum all worked out well on the iso and on the disc too. Now, what I did...I ticked all the first 3 options (acpi=off, noapic, noalpic) using F6 before on the installation screen to facilitate the installation. Now I've got the OS on the laptop, but after the installation I had to follow desgua's instructions and make the "acpi=off, noapic, noalpic" changes permanent.