Did you choose the menue: Button "Global" and so on?

I have a vague re-collection that, when using my old PC, I needed to very deliberately go through the following sequence:
Turn off SP4.
Turn on SP4.
Turn on PC and boot up.
Attach USB cable to SP4.
Attach other end of USB cable to PC.
Use a Load command in Global mode to load a soundfile.
... sounds obvious, but if I didn't follow this sequence religiously it wouldn't work.

I think I also read somewhere that, if your USB cable is very long, it may not work .... so maybe try a shorter cable.
Also, try to go directly into a USB port on your PC and not indirectly via an external USB hub.

Good luck. FYI, I recently generated some banks of User Setups to the Ksetlist site and I'm looking for feedback from other SP4 fans. So, hope you get your temp drive working so that you can try them out.
Best,
Roy

Operational Support will guide you step by step:

http://kurzweil.com/support/operational/

Thanks so far, tried your routine, watched Kurzweil support. Problem seems to be, I can´t make a connection between SP4 and PC, no matter which cable or USB port I try.
It always says "connect the PC".
Trying to update shows "update error 11"

Works!
Problem seems to be the USB Jack of the SP4.

Glad your virtual drive is working.
Did you have a chance to try out any of the SP4 User Setups (SPSetups) banks I uploaded? (they are in the "KSetlist Compilations/Volumes" area of the site.
Roy

Can I load one preset into SP 4 from PC. What file extensions can be loaded into SP 4? from PC 3? PC LE?

Yes you can load only one file, but there must be a free place in memory.
Besides the sounds from the kurzweil-homepage you can load *.PLE (from PC3LEx), too.
But watch up using PC3-files. I got lots of problems! Don't do this!
... And it is not neccessary, because you can get all this wonderful sounds in pc3LE-Format.
Good Luck!