When you double-click on the file to install the program, there are a few places here you have to click 'Next' to proceed. At the last one (I think) there are a couple of pre-ticked boxes. From memory, one invites you to install a desktop icon and the other invites you to take a trial of the 'Premium' version. It's that tick you should remove. (If you've got past there, without removing the tick, don't worry. You'll still be able to run the program, to get rid of the malware that's causing your problems).