You may try following to test if the oscilloscope is not defective:
If you have Windows Vista, Windows 7 or 8, locate the file PCSU200.ini in the folder:
C:\Users<username>\AppData\Local\Velleman\PCSU200
If you have Windows XP locate the PCSU200.ini in the folder:
C:\Program Files\Velleman\PcLab200
Open the file in any text editor and replace the file content with the following text and save the file:
[Calibration]
offs_1=112
offs_2=116
v5_offs1=-4
v5_offs2=1
Ch1_pos0=127
Ch1_pos1=32
Ch1_pos2=224
Ch2_pos0=127
Ch2_pos1=31
Ch2_pos2=224
Ch1_ad0=111
Ch1_ad1=54
Ch1_ad2=169
Ch2_ad0=115
Ch2_ad1=57
Ch2_ad2=173
[Menu]
HWdialog=0
Then run the PCLAB200.
The oscilloscope should work now OK without calibration.
There may be either a compatibility problem or the PCSU200 is defective.
Can you test the oscilloscope in other PC?
If you have Windows 7 or Windows 8 you can download and update to the driver available from this page: velleman.eu/support/download … U200&type=
Download, extract and update the driver: “Driver for Microsoft Windows 8”
After the driver update please check in the Device Manager the driver version number is: 13.54.20.543