QuickDownloadPack is a rogue download accelerator. It may be silently installed by a trojan or may be bundled with another rogue software such as SpywareRemover2009. Also it may be downloaded by the tricked user from the official site:
QuickDownloadPack is very dangerous because it capable to download and install other malware applications. QuickDownloadPack installs itself as Windows autorun application, so it starts automatically and stays resident in memory.
A browser helper object, or BHO, is a plug-in for the Microsoft Internet Explorer web browser. The BHO application programming interface exposes hooks that allow the BHO to access the document object model of the current page and to control navigation. Some exploits of this technology search all pages you view in IE and replace banner advertisements with other ads. Some monitor and report on your actions or change your home page.
