Windows 7: Cannot connect to public lan...everything tried...

Okay..I'm a newcomer here and I am Chinese, so my English is poor ~But i've got a trouble in my hometown library. The library has wired lan and wireless AP as well. the wireless connection works well but the wired one refuses to work.

Sth of my laptop
Clevo M570TU(PM45,Q9000,280MGTX,4G DDR3)

sth about the library network:
DHCP must be enabled for the server. A laptop with XP can easily connect to the server and get internet access. but for a vista one or Windows 7 one...the result is the same.

when plugged the wire, "Identifying...." then "Unidentified network" and "No Internet Access".
I tried the registry thing mentioned for vista (DHCP broadcast or sth else, you know) and the MAC modification way mentioned in other topics..not working...
btw, Realtek Adapter.

here is my ipconfig /all

Microsoft Windows [Version 6.1.7100]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\Lerista>ipconfig /all
Windows IP Configuration
Host Name . . . . . . . . . . . . : LL-Note
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
Wireless LAN adapter Wireless Network Connection:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek RTL8187B Wireless 802.11b/g 54Mbp
s USB 2.0 Network Adapter
Physical Address. . . . . . . . . : 00-22-43-90-85-CE
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::8134:1574:d580:1663%12(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.134(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.254
DHCPv6 IAID . . . . . . . . . . . : 218112579
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-11-CE-9D-42-00-90-F5-87-E5-D1
DNS Servers . . . . . . . . . . . : 202.98.0.68
NetBIOS over Tcpip. . . . . . . . : Enabled
Tunnel adapter isatap.{C33F6D79-F146-482F-8D7E-AB26724A4702}:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Tunnel adapter Teredo Tunneling Pseudo-Interface:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::818:1655:3f57:ff79%13(Preferred)
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 352321536
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-11-CE-9D-42-00-90-F5-87-E5-D1
NetBIOS over Tcpip. . . . . . . . : Disabled


Antivirus,NOD32.

This problem appears not only on my Windows 7, but also schoolmate's vista....

Help~~thx a lot