Well, to be honest, it is going to be a PITA - however, if you uninstalled them through Programs and Features then you should be able to delete the folders as well - however, in order to delete anything from Program Files you'll need administrative privileges, and then be asked to allow explorer to gain even higher privileges.
If your HD is even just a small 100 GB, then space used on there is a whole 0.4% of your drive space. Unless you are truly hurting for space, you may as well leave it alone, and make sure you reboot to see if it goes away after the reboot *before* you attempt to delete the folders manually.
Always, always, *always* reboot after uninstalling a program before deleting the remaining crud.