For this we have to use registry editor indirectly without encountering this BSOD error. For Windows 7 users their setup or recovery disc comes in handy for help. Also the operating system itself has inbuilt Start-up repair utility if PC crashes suddenly where it then proceeds to advanced options even it fails to fix it. But for XP users the only option is by using offline Registry Editors which are available in the internet world where anyone can download it for free. Among them I suggest a freeware utility here which can be used by both XP, Vista and 7 users.
[Last Updated on July 14, 2012]
I. Using Registry Editor from Recovery Console: (for Vista/7 Users)
1] Press F8 key before Start-up screen appears.
2] Select Repair Your Computer from Advanced Boot Options.
3] Select your language for keyboard layout. In the next window, Type the password for your User account. Now select Command Prompt from System Recovery Options tool.
4] At the command prompt window, type the command "regedit.exe" and hit Enter key,
II. Using Registry Editor from Hiren's BootCD: (for XP/Vista/7 Users)
1] Download Hiren's BootCD and make a bootable CD by burning the iso image.
2] Boot the infected PC with this CD by changing boot priority in BIOS menu.
3] Select Mini Windows XP option.
4] After Mini XP is loaded, click Start > Run > type regedit.exe > click OK.
5] In the registry window, click and select HKEY_LOCAL_MACHINE key.
6] Now click File menu > Load Hive and select SYSTEM file from C:\Windows\System32\config folder and click Open.
7] Now give a name as "newuser" (for example) in the popup text box.
8] Now navigate to HKEY_LOCAL_MACHINE\newuser\ControlSet001\Control\SessionManager\SubSystems and double click "Windows" key in the right pane.
9] Check the string as follows, if not then edit the string as it is given below.
%SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows SharedSection=1024,20480,768 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4 ProfileControl=Off MaxRequestThreads=16
10] The above bold word in the string must be checked specific, if not then edit it.
12] Similarly double click the "Windows" key from the path HKEY_LOCAL_MACHINE\newuser\ControlSet002\Control\SessionManager\SubSystems and edit the string as mentioned above.
13] Click OK and now click "newuser" hive > click File menu > Unload Hive.
14] Finally close the registry editor and restart Windows normally.
Note: If your Windows does not boot up normally and again crashes, read my post on How to fix STOP: c0000135, %hs error without registry editor. This may help even better you are looking for.