Perceptron 64 should be able to start without any Java installed on your Windows system. Otherwise, make sure that you have the right version of Java and reinstall it for the whole system.
The technical explanation of startup error may be as follows. See the following web site for the instructions on how to set Java path and if you are a programmer, other Java-related environment variables (classpath and java_home). Add the folder name where you stored the 64-bit version of Java Runtime Environment to the beginning of your path variable (that could be C:\Program Files\Java\jre8\bin). Visit the Java settings in Control Panel, go to tab Java, and press the button View. There you can press the button Find to scan for all Java environments on your computer. The first listed version will be used; usually, it is the latest 64-bit version. Then the startup should also work well.
Try to double-click perceptron.jar. If necessary, you can try to execute the old-fashioned perceptron32.bat or perceptron64.bat in the Perceptron folder, depending from the 32/64-bit type of system that you have, by clicking or from console. That will leave a console window open, where you can read the messages from Perceptron. Use Alt + Tab to switch to desktop and to switch between all running programs. In the past, Windows console has been a 32-bit environment in itself that used only 32-bit Java.
In the past, users also encountered another problem at startup, because the 32-bit Java for Windows updates itself automatically via internet and the 64-bit version does not. Over time, the 32-bit version would install itself as the primary version, so double-click to Perceptron.jar program would execute as a 32-bit program at a slow speed. If you manually set the Java environment variables, the problem will be solved and the helper applications will work (Perceptron 64.exe, perceptron64.bat).
At present, the 64-bit Java is indeed the default version that the Oracle installation program sets-up automatically through setup process of from Control Panel Java option where you search for Java runtime environments everywhere on your computer.
If Perceptron is running slowly even in 64-bit mode, you may have problems with Windows Power Management. Windows tends to use the minimum amount of processing power (CPU), so the CPU usage is minimal except when running very demanding program such as 3D video game. Then it increases operating frequency and power usage of CPU. However, that may not happen when Perceptron is running. Windows may leave CPU at its slowest speed. This is related with the Ati Radeon graphics driver, and may be further related with conflicting power management tools that are found in Windows, in Ati Control Panel and in motherboard utilities. Update your graphics driver and let it setup your computer for video gaming. That should give you settings you can use to run Perceptron fast. Later, you can try to reduce the lower limit of CPU frequency in Ati Control Panel and cool down the system.