Brontok AJ virus

hello,
I´ve currently been trying to get rid of the Brontok worm(think it´s the .AJ one) for a week and am finding it less than easy. It was passed onto my computer by a pen drive, I don´t have the net on it. I ran kaspersky antivirus which removed the dodgy exe files, but didn´t remove anything from the windows folders or the registry. I Have downloaded various tools, Bitdefender(which enabled me to access folder options again) Brontgui, the sophos tool and Brontok washer I think but none of them have got rid of it fully. There are still dodgy files in Windows System32 folder an probably elsewhere, but if I try to delete them, it says "access denied". Is there anyway to get rid of them?
Another thing.. if I bring up the task manager window and look at processes, I can see dodgy things like winlogon.exe and "smss" and lsass" or whatever it is running, if I try and remove them aagain it won´t let me. What exactly are these programs doing, and how can I remove them?
One final question.. in the state that my computer´s in, i.e, folder options available, registry edit available, no dodgy .exe files elsewhere but in win folders, no restarting, do u think it´s infectious still? I mean if I put a disk in, will it become infected? I have put a disk in and run antivirus on it and it doesn´t find anything, so I don´t know.
Also how do I check for dodgy things in the registry?
Thankyou very much for any help