VPN connects, but can't see server. Other computers on same network can

Question

One of my computers that use the VPN has been working fine for many months. But now it connects to the VPN and the internet works just fine but I cannot browse the server or get Outlook to connect to Exchange.

Another computer on the same home network connects fine and can access everything. They are both using exactly the same login details.

I am running SBS 2003 and VPN from Windows XP, Vista and 7.

Any ideas?

Here are the details of the config:

IP Config

Windows IP Configuration

Host Name . . . . . . . . . . . . : JoWright-Antec
Primary Dns Suffix  . . . . . . . : 
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection 2:

Connection-specific DNS Suffix  . : 
Description . . . . . . . . . . . : NVIDIA nForce 10/100 Mbps Ethernet #2
Physical Address. . . . . . . . . : 00-E0-4D-05-3D-4D
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.0.106
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.1
Lease Obtained. . . . . . . . . . : 08 September 2011 19:09:09
Lease Expires . . . . . . . . . . : 09 September 2011 19:09:09

PPP adapter Time Communications:

Connection-specific DNS Suffix  . : 
Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface
Physical Address. . . . . . . . . : 00-53-45-00-00-00
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.0.143
Subnet Mask . . . . . . . . . . . : 255.255.255.255
Default Gateway . . . . . . . . . : 192.168.0.143
DNS Servers . . . . . . . . . . . : 192.168.0.2
Primary WINS Server . . . . . . . : 192.168.0.2

Route

===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ...00 e0 4d 05 3d 4d ...... NVIDIA nForce Networking Controller #2 - Packet Scheduler Miniport
0x40004 ...00 53 45 00 00 00 ...... WAN (PPP/SLIP) Interface
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      192.168.0.1   192.168.0.106   21
          0.0.0.0          0.0.0.0    192.168.0.143   192.168.0.143   1
     88.96.104.86  255.255.255.255      192.168.0.1   192.168.0.106   20
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1   1
      169.254.0.0      255.255.0.0    192.168.0.106   192.168.0.106   20
      192.168.0.0    255.255.255.0    192.168.0.106   192.168.0.106   20
    192.168.0.106  255.255.255.255        127.0.0.1       127.0.0.1   20
    192.168.0.143  255.255.255.255        127.0.0.1       127.0.0.1   50
    192.168.0.255  255.255.255.255    192.168.0.106   192.168.0.106   20
    192.168.0.255  255.255.255.255    192.168.0.143   192.168.0.143   50
        224.0.0.0        240.0.0.0    192.168.0.106   192.168.0.106   20
        224.0.0.0        240.0.0.0    192.168.0.143   192.168.0.143   1
  255.255.255.255  255.255.255.255    192.168.0.106   192.168.0.106   1
  255.255.255.255  255.255.255.255    192.168.0.143   192.168.0.143   1
Default Gateway:     192.168.0.143
===========================================================================
Persistent Routes:
  None

The IP addresses are reserved for the VPNs.