i quote "The Registry contains information that Windows continually references during operation, such as profiles for each user, the applications installed on the computer and the types of documents that each can create, property sheet settings for folders and application icons, what hardware exists on the system, and the ports that are being used".
click
http://support.microsoft.com/kb/256986/EN-US/#Topic1
normally it is safe to delete invalid registry keys which are detected by registry cleaners. but i have not used RegSeeker, so cannot comment on it. some programs are known to screw things up, so be careful. prima facie it appears safe to delete the mentioned registry entry.
ace utilities, tune-up utilities, winaso registry optimizer, system mechanic, ccleaner, super utilities are some of the safer registry cleaners which u can try. click
www.download.com.