Theres an app I used to use which gives an analysis of any log file, but unfortunately I really cant recall what it is called now as its been so long. Maybe Woosty might know? I'd need that app to make sense of any log files...
You may find this site good for testing suspected files, but wont really help at this point until you've pin pointed the suspected location of the rejuvenating source... theres a good chance the rejuvenator is in your system 32 folder for example...but you'd still need to know the specific suspected dll/file/exe etc
http://virusscan.jotti.org/en The site will upload any file/exe of your choosing and scan it with all the av's around. Prob not going to help at this stage though.

You've definitely checked your start up entries? Though may not show on there if its running from system 32 etc...
See what Avira reckons.