Hello everybody! 
  if this question has allready been answered; forgive me, but I wasn't able to find it (and I really tried). 
  I'm using a NI USB-GPIB-HS cable to communicate with a Keithley 2000 multimeter (with a SCAN multichannel card), and Labview 8.0. The program I wrote read resistance on different channels. As I was testing it, at a certain point I ran the program with Keitley turned OFF. A lot of erros prompted the screen and I aborted the program. Then I turned Keithley on again and ran the program, but whatever I do, I keep getting a NI 488.2 error: 'No board present' on the screen.  
 I've restarted the computer, and Keithley -> didn't work. 
 Reinstalled the drivers -> didn't work 
 Changed the GPIB adresses (both Keith and program) -> didn't work 
 Tried to see if the USB-GPIB-HS card has been damaged by running the Mesurement and control; Ni 488.2 analyzer , but it failed to detect it. However, this test isn't conclusive because I also ran it on the other computer where I have a GPIB-PCI card and it also didn't detect it. 
 Both LEDs  ('ready' and 'active') od the USB-GPIB-HS cable are blinking (not at the same time..) during the test. 
 Also I've installed the 8.0 ->8.0.1 ->8.2.1. update, though my Labview says it's a 8.0.1 version. Is it possible that there is some kind of a bug with the update? (Though I don't believe that, cos the program ran smoothley with the updates before the program was ran with Keithley turned OFF..). 
 If somebody had a similar problem and solved it -> please let me know. 
    Thanks. 
    Mihael