Adware:Adware (or spyware) is a small program that is designed to show advertisements (in various form and degrees of intrusiveness) on your computer. It often reports personal information back to its owners. As a result your sense of privacy can be violated.
Lets Search is an Internet Explorer toolbar that provides specialized search functions. The adware may redirect your search requests to its controlling server and may also generate advertisements on your computer.
Technical details (How to remove LetsSearch(pop up))