Mste has an internal HD. Mega ST has not.
If drive C is not shown after the startup sequense, then I suggest you use an external program like Hddriver, or you can download ICD drivers from the net. Hddriver-demo can also be downloaded freely. In attachement you get the ICD driver. Found at http://www.icd.com/atari/
You can boot you system, as explained above, and check with the above programs if they 'see' you HD. You can use for that IDCHECK.PRG (included in the above package).
If yes, then you has a software problem, and with the external driver you can probably access the HD. If it don't show the HD, may-by you get an Hardware problem.
But you don't need ICD drivers for your ICD adapter. As example, I use Hddriver together with my ICD adapter. You can use others too.
Normally when the Atari HD is correct installed, the boot-up goes automaticely. It don't need any handling.
If you download some stuff from a Pc, and put it on a diskette, you must consider that the Mst has a DD floppy drive, and if you use winXP, it gives problems to access DD diskettes. I use always linux for access my diskdrive with DD diskettes.
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