teleservice 6.0 uninstall problem

A[:cry:]
fter 15 trial days passed, I decide to uninstall teleservice6.0 and re-install teleservice 5.2.
But each time find a error:
_Wtsadpterputparams50@280 can't  link to s7wtsDlx.dll
seems Ver6.0 left some body in my PC
how can I clean my PC to make Ver5.2 live again or
start another trial period just use Ver6.0 temporary to skip my boss's long face.
I use windows2000 and Step7 5.3
Please some one can help me send your reply to mail: mxwen@263.net
With thanks and regards