Context menus, web pages and programs slow to open after malware removal ?

After cleaning your computer from some recent trojans/backdoors/rootkits, there may be remnants left in the Windows Registry pointing to non-existent dynamic libraries and startup items that slow down the machine to a crawl when opening programs and context menus.

Short of a clean Windows install, first do a Hijack This cleanup, and then check the following key (using regedit):

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\AppCertDlls

If there are values under it pointing to non-existent files/folders, chances are they are leftovers from malware cleanup and can be safely removed. This should immediately and very noticeably speed up right-click context menus and program startup times.