I guess the biggest problem with your question is "running as it should" is merely a subjective term. Everyone has their ideas about what is an what isn't "running as it should" I for instance have the pagefile turned off as I have 512mb of RAM and do not act as a server or on a LAN. This is to me a performance tweak while to others it is counter productive. I simply hate the useless system restore and instead use the backup tool NT Backup that microsoft chose to hide on the XP disks, and so on. In my opinion the best tool your system has is the event viewer. In there you will see red X's that will give you clues to any of the system problems you are having and sometimes even ways to fix them. I have Norton System works and have found that there are far superior and free tools out there. Although I think that Norton Anit-virus is one of the best.
Get a good registry cleaner (i.e., Registry First Aide), a registry compressor (i.e., Registry Compressor Pro) and a good defrag program (i.e., PerfectDisk 2000) and your OS will run like a fine-tuned Swiss time-piece.