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.
AdStartup is an adware program that monitors your web surfing habits and then transmits this information back to its parent server in order to build a marketing profile associated with your computer. AdStartup is a variant of AdLogix. In some cases, this parasite is installed with a rootkit to prevent detection and removal.
Technical details (How to remove AdStartup(pop up))