the PCAN-Explorer 3 does not work on Windows 7 32 or 64 Bit Version.
You could try to use the PE3 in the XP-Mode of W7 (virtual-PC) which is part of the W7 Pro Versions.
This work fine with the PCAN-USB Interface (does not work with PCI based cards).
But please check up in front if you have the latest PE3 Version (Version 188.8.131.524), if not send a E-Mail with your serialnumber of yor PE3 to info[at]peak-system.com, and we send you the download for the latest PE3.
Please use only the latest drivers to install the CAN Interface on new PCs
- Support - Download packages)
Download the version for the CAN Hardware you use, unzip the files, and start the PeakOemDrv.exe to install the driver and the PCAN-View Monitoring Tool.
You also could update your PE3 to the latest Version PE5, which work fine on W7 32/64Bit. Here some more information: http://www.peak-system.com/forum/viewtopic.php?f=50&t=83