[solved]splash screen hangs(not the app) - how does the memory usage work?

I have been using Firefox portable 1.5.0.3 with winXP sp2 for some years, now. It always worked fine.
Last week, I got a virus from a streaming page. I knew it was a malware because of the sudden lag i experimented. I had to force the closing of Portable Firefox. I think I have got rid of the virus manually (CPU usage normal, network requests normal).
But since that virus came, the splash screen of the portable apps (portable firefox and minefield) doesn't disappear although firefox works normally. I tried Compreg and Chromfix without any effect. Then, I tried disablesplashscreen and waitforfirefox with success for both. However, the last one has changed behaviour since a manipulation. From being visible until Firefox closes, it turned into the usual way : _sp shows then disappears before firefox starts.
Do you know the files or keys in registry that are used during the splash screen, so that I can fix the remains of that virus?

Sorry, it was as short as possible, for a first post of a problem :?.