If after installing VeSys you ONLY get the VeSys Components icon and you DO NOT have a VeSys Design or Harness icon on the desktop it is likley that VeSys has not detected a supported version of AutoCAD. This could be for a number of reasons but the most common is that you have a later version of AutoCAD than the version of VeSys was designed for, if this is the case go to supportnet and download the latest version.
Note: A service pack may actually be the latest version of the software, these service packs are actually full installations of VeSys (at least up to 2008.1 SP1) and so you do not need to download 2008.1 and then the Service Pack.