You may have a bad
driver installation.
With the PVR connected and on, Go to Control Panel > Programs and find the Hauppage
driver program (if listed) and uninstall it from there. If there is no listing for the
driver then just uninstall all of the other software.
If the driver is not in Programs then go to Device Manager and find the PVR listing there, go to the Driver Tab and uninstall the driver. After the driver and all software is removed unplug the unit from the PC.
Now here is where you have some decisions. It would be best to use System Restore to restore the computer to a date before you first installed the PVR. If that date was too long ago then forget it.
You could use a program like CCLeaner to find and remove any remnants of the program if System Restore is not an option.
Then download (again if you have it - some downloads get corrupted) the "HD PVR Driver Version 1.6.29277" from the Hauppauge website.
If it were me I would try to install the driver first, then plug in the USB cable from the PVR (contrary to the Installation Instructions in the Quick Start Guide). Otherwise Windows may just find the old driver file from the Driver Store and reinstall it.
The unit should not crash your system. You need to be sure it is installed and operating correctly in Windows before you tackle the Operational issue.