Last time I did a reinstall was 1.5 years ago. I don't have any problems and don't see the need to reformat/reinstall. Some people do it twice/year though. Any reason to reformat/reinstall? I use revo uninstaller and regularly clean with ccleaner. Also, what is the best free registry cleaner out there? I use the CCleaner one but it doesn't seem to get everything. Figure that if I clean the registry and delete unused programs, i shouldn't have to reformat often, right?