While this FAQ mainly deals with Access 2000 Runtime files, I am sure that the same will be true for earlier versions. All information is based on previous experience.
NEVER install Access Runtime files to the default directory if any version of Microsoft Office has been installed. From experience I have found that, certainly with earlier versions of Office, parts of Access already exist in the destination folder and overwriting/changing these can have a disastrous result in both Office and Access Runtime. Even if the Full Version of Access is uninstalled prior to Runtime installation, many Access files are left in place and will be corrupted by the Runtime installation. Doing this can lead to no end of problems, e.g. Database no longer performs, runtime errors and other miscellaneous errors.
ALWAYS install Access Runtime files to a completely separate directory. I have found intalling Runtime to a different directory has no detrimental effects on the performance of the Runtime solution. This way it is kept separate to the installation of Office, preventing any corruption and allowing use of all of the functionality provided with Access Runtime. No corruption will ensue due to the fact that there are no Access files already present in the directory.