If your running winxp w/ sp2, try the following to reset tcp/ip:

Click Start, click Run, type netsh winsock reset catalog, and click OK

if otherwise, follow these steps:

To remove Winsock settings with systems running Windows XP Service Pack 1 or lower, perform the following steps:

1. Click the Start button, then click Run.

2. Type regedit and click the OK button.
The Registry Editor window appears.

3. Click the "+" to the left of HKEY_LOCAL_MACHINE.

4. Click the "+" to the left of SYSTEM.

5. Click the "+" to the left of CurrentControlSet.

6. Click the "+" to the left of Services.

7. Scroll down to locate the Winsock folder.

Right-click Winsock and click Delete.
The Confirm Key Delete window appears.
Click Yes.

Right-click Winsock2 and click Delete.
The Confirm Key Delete window appears.
Click Yes.

8. Restart the system.

To reinstall winsock and tcp/ip, follow these:
After removing the Winsock settings, perform the following steps:

1. Click Start, and then Control Panel.
The Control Panel window appears.

2. Double-click the Network Connections icon.
The list of available connections is displayed.

3. Right-click Local Area Connection and left-click Properties.
The Network Connection Properties window appears.
On the General tab, click Install.
The Select Network Component Type window appears.
Click Protocol, then click Add.
The Select Network Protocol window appears.
Click Have Disk.
The Install From Disk window appears.
Type C:\Windows\INF and then click OK.
Click Microsoft, then click Internet Protocol (TCP/IP) and click OK.
The Network Connection Properties window appears.
Click Close.

4. Restart the system.

5. Click Start, then click Run.

6. Type netsh int ip reset tcpiplog.txt in the Run line and click OK.

You should be good to go.