Did you try to install CIS in Safe Mode? That will not work because Windows Installer does not work in Safe Mode.
Since you say you install a lot of programs I take you are not shy of editing the registry. See if the following manual instructions do the job for you.
Delete the Comodo folders under Program Files, Program Files\Common Files,
For XP : c:\Documents and Settings\All Users\Application Data\ .
For Vista/Win7: Users%username%\appdata\local, Users%username%\appdata\roaming\ and \Users%username%\appdata\local\virtual store
Now delete the following:
C:\boot.ini.comodofirewall (this file may not exist).
WARNING: Do not mistakenly remove the original “boot.ini”.
C:\WINDOWS\system32\drivers\cmdGuard.sys
C:\WINDOWS\system32\drivers\cmdhlp.sys
C:\WINDOWS\system32\drivers\inspect.sys
C:\WINDOWS\system32\drivers\cmderd.sys
C:\WINDOWS\system32\guard32.dl
C:\WINDOWS\system32\drivers\sfi.dat (this file belongs to stateful inspection of the AV )
a. HKEY_CURRENT_USER\Software\ComodoGroup\CFP and HKEY_CURRENT_USER\Software\ComodoGroup\Comodo Internet Security
b. HKEY_LOCAL_MACHINE\SOFTWARE\ComodoGroup\CDI\1 *
*(If you have other Comodo products installed, delete only the values
for CFP)
c. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services cmdAgent
d. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\cmdGuard
e. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\cmdHlp
f. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Inspect
fi. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\cmderd
g. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\cmdAgent
h. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services \cmdGuard
i. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\cmdHlp
j. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\Inspect
ji. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Services\cmderd
k. KEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\cmdAgent
l. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\cmdGuard
m. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\cmdHlp
n. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\Inspect
ni. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\cmderd
o. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\cmdAgent
p. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\cmdGuard
q. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\cmdHlp
r. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Inspect
ri. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\cmderd
s. HKEY_LOCAL_MACHINE\SYSTEM\Software\Comodo\Firewall Pro
t. HKEY_USERS\S-1-5-21-1202660629-746137067-2145843811-1003\Software\ComodoGroup\CFP
u. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CMDAGENT *
v. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CMDGUARD *
w. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CMDHLP *
x. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_INSPECT *
xi. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CMDERD *
y. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Enum\Root\LEGACY_CMDAGENT *
z. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Enum\Root\LEGACY_CMDGUARD *
aa. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Enum\Root\LEGACY_CMDHLP *
bb. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Enum\Root\LEGACY_INSPECT *
bbi. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet002\Enum\Root\LEGACY_CMDERD *
cc. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\LEGACY_CMDAGENT *
dd. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\LEGACY_CMDGUARD *
ee. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\LEGACY_CMDHLP *
ff. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\LEGACY_INSPECT *
ffi. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\LEGACY_CMDERD *
gg. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_CMDAGENT *
hh. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_CMDGUARD *
ii. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_CMDHLP *
jj. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_INSPECT *
jji. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root\LEGACY_CMDERD
kk. HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\CFP_Setup_3.0.14.276_XP_Vista_x32
ll. HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\CFP_Setup_3.0.14.276_XP_Vista_x64
mm. HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\CFPLog
nn. HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\CPFFileSubmission
oo. HKEY_LOCAL_MACHINE\SYSTEM\Software\Comodo\Firewall Pro
To remove the socalled Legacy Keys, which are otherwise hard to remove, open Device Manager from the command prompt using the following two commands:
set devmgr_show_nonpresent_devices=1
start devmgmt.msc
Set Device Manager to show hidden devices under menu option View. Then see if there are Comodo Internet Security related drivers left in non Plug and Play drivers. If so select the driver → click right → uninstall. Do this for all present drivers. Do a reboot when it has been requested. See second image.
Sometimes it happens that you can’t connect to the internet after uninstalling, using the unofficial clean up tool or trying a manual deinstallation. Then the Inspect driver is still present and needs to be uninstalled.
How to uninstall the CIS firewall driver when it stays present? Look up the properties of the network connection, select the Comodo Firewall driver and uninstall it. See the attached image.
Reboot when requested.
[attachment deleted by admin]