I had similar problems once, when some cd-related soft installed adaptec 4.60 aspi. If you remove it manually (that means: remove files, remove registry entries, eventually uninstall aspi32 from device manager with show hidden devices turned on) and reboot, everything should be ok.
I have 401@411, nf2 native ide driver works very well with it (version 3.66).
Bottom line - imo - don't use any adaptec's aspi. There're so many problems with it... check this thread for some more details: click