Can't delete Rohos Logon key software, no Admin access either

I am on OS X 10.6.8 and am having problems with Rohos Logon key.

I tried to delete all the Rohos Logon files but have missed some as I get my login screen only momentarily and then it disappears so am unable to login to make changes that require a login. The unistall app from Rohos doesn't see anything so is not picking up on any hidden or related files.

I have not used the software to create a USB key.

This software is a disaster.

Their website describes a way to uninstall Rohos Logon key but it is far from clear how or whether this works, the language/grammar is really dodgy.

http://www.rohos.com/products/rohos-logon-key-for-mac/troubleshooting/

This is only a recent install of their software, last 4 weeks, so whats the best solution to getting my login window back to normal?

Is it possible to circumvent the Rohos software by changing my admin password?

Or should I do an install of Snow Leopard (not a clean install) over the existing OS and apply the updates?

Although I use Time Machine the oldest backup is only 3 weeks old as the HD had to replaced (Failed LaCie 1 TB unit, now running a 2 TB WD).

Any help wd be much appreciated.

24" iMac, OS X 10.6.8, 2 TB WD Time Machine HD