Windows Setup could not configure to run on this hardware

Hi,

This is my hardware:

Dell XPS L521X
Intel Core i5
4GB RAM
500GB Sata 3 HDD + 32GB mSata SSD

This is what I've done:

1) I had to reinstall Windows 7
2) Booted from Windows 7 installation disc, no hard drives found
3) Changed Sata Operation in bios from Intel Smart Response Technology to AHCI
4) Went into Windows' repair mode (F8 during start up) --> command prompt --> disabled the SSD --> disabled acceleration of any HDD
5) Changed Sata Operation  in bios again from AHCI to Intel Smart Response Technology
6) Tried to install Windows 7 again, hard drives found, installation almost completed but went wrong at the end: "Windows Setup could not configure to run on this hardware"
7) I rebooted a few times, didn't help

Now I can't use my laptop anymore at all, so any help would be greatly appreciated!

Many thanks in advance,

Stefan