关于INF文件的一点疑问！

自己写了一个INF文件，如果是用指定设备的方式去安装没有问题，
如果让系统自己去搜索软盘上对应的INF文件和驱动程序，系统竟然提示找不到该设备对应的驱动程序，请问是什么原因造成的？ :D

I am also a beginner.
But I think,you should check the following firstly.
1.whether you have built a *.sys or not.
2.check your INF file.
  Did you define the section [SourcesDisksNames]?

Would you mind to paste the content of INF file?

;; SnUSB.inf - Install Information File
;; Description:  SinoData WangSheng 2002/10/11 Fix

[Version]
Signature=\"$Chicago$\"
Class=SinoData HardWare
ClassGUID={ff646f80-8def-11d2-9449-00105a075f6b}
Provider=%ProviderName%
Revision=1
DriverVer=10/10/2002, 1.0.0.1

[SourceDisksNames]
1 = \"USBReader Driver Installation Disk\",,

[SourceDisksFiles]
SnUSB.sys = 1

;---------Windows 9X Style----------

[ClassInstall]
Addreg=Class_AddReg

[Class_AddReg]
HKR,,Icon,,-5

;---------Windows NT Style----------

[ClassInstall32]
Addreg=Class_AddReg32

[Class_AddReg32]
HKR,,EnumPropPages32,,\"SnHWNT.dll,EnumPropPages\"
HKR,,Icon,,0

[DestinationDirs]
SnUSB_Files_Driver = 10,System32\\Drivers
;SnUSB_Files=10
SnUSB_Files32=10,System32

[Manufacturer]
%MfgName%=Mfg0

[Mfg0]
;%DeviceDesc%=SnUSB_DDI, USB\\VID_1234&PID_0005
%DeviceDesc%=SnUSB_DDI, USB\\VID_7890&PID_0001

; --------- Windows 9X -----------------
[SnUSB_DDI]
CopyFiles=SnUSB_Files_Driver
AddReg=SnUSB_9X_AddReg

[SnUSB_9X_AddReg]
HKR,,DevLoader,,*ntkern
HKR,,NTMPDriver,,SnUSB.sys
HKR, \"Parameters\", \"BreakOnEntry\", 0x00010001, 0

; --------- Windows NT -----------------
[SnUSB_DDI.NT]
CopyFiles=SnUSB_Files_Driver,Snpci_Files32
AddReg=SnUSB_NT_AddReg

[SnUSB_DDI.NT.Services]
Addservice = SnUSB, 0x00000002, SnUSB_AddService

[SnUSB_AddService]
DisplayName    = %SvcDesc%
ServiceType    = %SERVICE_KERNEL_DRIVER%
StartType      = %SERVICE_DEMAND_START%
ErrorControl   = %SERVICE_ERROR_NORMAL%
ServiceBinary  = %10%\\System32\\Drivers\\SnUSB.sys

[SnUSB_NT_AddReg]
HKLM, \"System\\CurrentControlSet\\Services\\SnUSB\\Parameters\",\\
\"BreakOnEntry\", 0x00010001, 0

[SnUSB_Files_Driver]
SnUSB.sys

[SnUSB_Files32]
SnHWNT.dll

[Strings]
ProviderName=\"SinoData\"
MfgName=\"SINODATA\"        
DeviceDesc=\"SinoData USB Reader Driver 2002.10.10\"
DeviceClassName=\"USB Reader\"
SvcDesc=\"USB Reader\"

SPSVCINST_ASSOCSERVICE=0x00000002 ; Driver service is associated with device being installed
COPYFLG_NOSKIP=2 ; Do not allow user to skip file
SERVICE_KERNEL_DRIVER=1
SERVICE_AUTO_START=2
SERVICE_DEMAND_START=3
SERVICE_ERROR_NORMAL=1

这是我装驱动的一些提示，它的提示为\"无法为设备找到一个驱动程序\"但是我点击下一步按钮，缺又可以装成功，why? :D