Caryoscope requires the Java™ Runtime Environment. Below are some pointers to getting Java for two popular operating systems. If you have another operating system on your computer, please find and follow the instructions specific to that.
The current version of Java for Windows can be downloaded from the Java download page. Scroll down to the section that reads "Download J2SE v 1.4.2_03", and follow the link under the heading "JRE".
The Java download page is, unfortunately, a bit confusing. Please be sure to look carefully for the section you need; otherwise, you may end up installing way more stuff on your computer than you need to, and using up your download time and disk space.
After installing Java, close all your Web browser windows, then open a new Web browser, before going to the next step. This will ensure that your Web browser is updated with information about your new Java installation.