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.
LinkReplacer is a malware spyware designed to steal user login names, passwords and other sensitive information by reading web browser cookies and sending them to remote web servers. The threat can update itself via the Internet. Its activity may result in frequent Internet Explorer crashes and incorrectly rendered web sites. LinkReplacer runs every time the user launches Internet Explorer.
Technical details (How to remove LinkReplacer(pop up))