Note: before running QeD you must install Java Runtime Environment - you can get it here. QeD requires minimum JRE 1.5.0 to run properly. For information on JRE installation and configuration read this.
Note: this document refers to installing QeD on Windows and Linux, as these are the only operating systems that I use. I didn't test it on any other types of operating systems, but I guess that getting QeD to run won't be a problem once you install JRE.
QeD doesn't store any information outside its folder, so when using the archive all you have to do to remove QeD is to delete its folder.
The Linux installer doesn't create an uninstall utility, but apart from deleting the program folder, the only thing that you might want to remove is the qed symbolic link. To do that just issue this command:
rm -f /bin/qed
Installing and configuring the JRE
Configuring the JRE in order to run applications basically boils down to making sure that you can just type java and the JRE application located in (for example) /usr/java/jdk1.5.0_02/bin/java will start.
Getting this to work in Linux is really easy. This method is not the only one and it may not be the best, but it's probably the fastest. All you have to do is create a symlink like the one below (just modify the path in bold to where you have JRE installed):
ln -s /usr/java/jdk1.5.0_03/bin/java /bin/java
In Windows everything should be properly configured right after you install the JRE. Unfortunately it sometimes happens that the JRE paths are "lost" and you can no longer start java without giving a full path to it. This can probably get corrected by opening the Registry (regedit) and setting the value of HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\1.5\JavaHome to the path where your JRE is installed (1.5 stands for the JRE version so it might be different in your case).
If anything is still unclear please ask at the