哪位大侠帮忙！我的INF文件不能更新驱动，这是为什么？

  我自己写了一个驱动和INF文件，当驱动装好之后，我想更新以下驱动，可总还是安装的systerm32\drivers下的那个驱动，新驱动这样安装不了，每次我都是删除inf目录下的inf文件才能更新驱动。哪位大侠知道这是怎么回事？
先谢谢了！
以前法帖总没人回，希望这次哪位帮帮忙啊!

我的INF文件如下：

;--------- Version Section ----------------------------------

[Version]
Signature = "$CHICAGO$"
Provider  = %tst%
DriverVer = 06/21/2005,1.2.1.0
Class     = CiDevicesClass
ClassGuid = {BF24CCC7-8222-4dd0-8D4E-BD2727CEA457}

;--------- ClassInstall/ClassInstall32 Section --------------

; Not necessary if using a standard class

; NT Style
[ClassInstall32]
Addreg = Class_AddReg

[Class_AddReg]
HKR,,,,%DevClassName%
HKR,,Icon,,"-5"

;--------- SourceDiskNames and SourceDiskFiles Section -----------------------

[SourceDisksNames]
1 = "WDM Install Directory",,,

[SourceDisksFiles]
hello.sys = 1,,

;--------- DestinationDirs Section --------------------------

[DestinationDirs]
DefaultDestDir = 10,System32\Drivers

;--------- Manufacturer and Models Sections -----------------

[Manufacturer]
%tst% = Mfg0

[Mfg0]
%DevName% = Install_WDM, PCI\VEN_11c6&DEV_4526

;---------- Windows NT Install Sections --------------------------------

[Install_WDM.NT]
CopyFiles = CopyFile_WDM
AddReg    = AddReg_NT_WDM

[Install_WDM.NT.Services]
Addservice = WDM, 0x00000002, AddService_WDM

[AddService_WDM]
DisplayName    = %DevName%
ServiceType    = 1                  ; SERVICE_KERNEL_DRIVER
StartType      = 3                  ; SERVICE_DEMAND_START
ErrorControl   = 1                  ; SERVICE_ERROR_NORMAL
ServiceBinary  = %10%\System32\Drivers\hello.sys

[AddReg_NT_WDM]
HKLM, "System\CurrentControlSet\Services\WDM\Parameters",\
       "BreakOnEntry", 0x00010001, 0


; --------- Files (common) -------------

[CopyFile_WDM]
hello.sys,,,2

;--------- Strings Section -----------------------------

[Strings]
tst          = "WDM Book"
DevName      = "WDM test"
DevClassName = "CiClass"

各位大牛，帮帮忙！急啊！
 

难道没有大牛愿意帮忙吗？