"You should first change settings in BIOS (after pressing F2 during the boot) to allow advanced boot options (by default it was set to disabled). After this change F8 started to work (previously system did not respond to pressing F8).

After selecting F8 a menu shows with many different options. You should select "Repair computer". Afterwards there is another menu. If you want to go for reinstalling Windows7 from scratch and deleting all your data, you should pick last option which is "ImageX Recovery...". Another hard to guess action.

To reasume, two tricks needs to be done (changing Bios first, selecting Repair computer and then ImageX recovery - secondly)"