Thank you. I used virtualbox (windows XP) with connected USB flash drive. I extracted SP60365_E.exe. I found two files SP60365_E.exe and SP60365_F.exe (depends of system) in C:\SWSetup\SP60365\hpqflash. Exactly these files create bootable flash drive.
Flashing in DOS for the business desktops seems to be less difficult.
All you do is copy the contents of the DOS flash folder to a fat32 formatted flash drive, plug it into the PC, go into the BIOS, where there is a menu to flash system OM. You select that, you select your USB flash drive from the list of options (CD or USB) hit the enter key and off it goes.