You need to do a "Windows Clean Uninstall". Instructions for that can be downloaded at:
www.tascam.com
or see below:

Under some troubleshooting or update circumstances, users may want to reproduce a "fresh installation"
condition on a particular PC. In other words, you will want the computer to be in the state it was in before an
FW-1884 was installed for the first time.
(Note: these instructions assume that Windows is installed in the usual location on the C: drive of your
computer. For Windows 2000, this would be c:\winnt. For Windows XP, this would be c:\windows. If Windows
is installed on a drive or folder other than these defaults, please modify the instructions below accordingly.)
To perform a fresh reinstall, you'll need to delete references to the FW-1884 in the computer:
A. Delete the following files from c:\winnt\system32\drivers (Windows 2000) or c:\windows\system32\drivers
(Windows XP):
* Fw1884.sys
* Fw1884Wdm.sys
B. Delete the following files from c:\winnt\system32 (Windows 2000) or c:\windows\system32 (Windows XP):
* Fw1884A24.DLL
* Fw1884cp.CPL
* Fw1884Panel.EXE (You will have to end the task via Windows Task Manager before Windows will
let you delete the file. Use CTRL+ALT+DELETE, and end the task from the Processes tab of the task
manager.)
C. Delete the following files from c:\winnt\inf (Windows 2000) or c:\windows\inf (Windows XP):
The oemX.inf and oemX.pnf files (X=0,1,2,...) which refers to the FW-1884. (Use the Windows Find.. utility to
determine which files contain the string "FW-1884")
Note that to make the INF folder visible, you may have to go into Windows Explorer and choose Tools | Folder
Options | View, and then check “Show hidden files and folders.”
D. In the system Registry, delete the following keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\FW1884
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\1394\TASCAM&FW-1884
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Fw1884
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Fw1884WdmService
You may have to use RegEdit32's (Windows 2000, c:\winnt\system32) or RegEdit’s (Windows XP,
c:\windows) Edit | Permissions dialog to set “Full control” to “Allow” before you are able to delete some of
these keys.
E. For even more extreme system cleaning (usually this isn’t necessary), find this key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceClasses
Then search for the string "FW1884" underneath it. Delete the entries that "own" these keys.
For example: the key
##?# FW1884#*FDG0007#0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}
has a key "#WaveA1" which has a key "Device Parameters" with an entry "FriendlyName" set to the string
"FW1884 Analog 1:2" Delete the entire key ##?FW1884... (etc).
Repeat this step until no more FW1884 occurences are left in the DeviceClasses key.
F. Finally, you can run the uninstaller found at Start | All Programs | FW-1884 to remove the driver files from
the temporary folder from which they were originally installed.