For a new built computer with Vista 32bit Home Premium, I installed a fax modem made by Creative Lab and later replaced with a US Robotic one that works. After uninstalling everything belongs to Creative product and the modem, the register reminder tap is not just pops up every once a while but stay on and flips between the registration tap no mater what I do to it.

I try to select never remind me or remind me in two week..... Won't go away.
I try to register as suggested.... Won't go away.
I try CCleaner.....Won't go away
I try Adaware .....Won't work

I don't have any creative product on my computer. Please help me to turn it off. Or do I have to reinstall my OS?

Do just a hijackthis log as per the instructions here - Viruses/Spyware/Malware, preliminary removal instructions and it shouldnt be to hard to get rid of.

go to windows task manager and check out the processes that are running. Find the one that is enabling the program. disable it or delete it.

also download mike lin's startup editor, and stop it from starting in the first place.