The install.log file is where all of the files and changes made to your system are stored. Without that file it has no idea what exactly to delete and restore, so the uninstallation cannot proceed. The general procedure would be to rip its guts out. That is, go to C:\Program Files and delete the program's folder, remove references to it from the start menu (right-click and delete), run a registry cleaner to remove the unneeded entries (RegCleaner is a good free one), clean up the junk files (CCleaner is the best freebie), etc. However, doing that can cause problems with certain programs, particularly ones related to security or customization software. In that case there are usually specialized uninstall instructions or uninstallers available from the software designer. Thus, the name of the program you are trying to remove, along with the problems you are experiencing, are needed for a complete diagnosis.

Hope this helps and let us know more.