Question : Cannot acquire IP address

I have a Toshiba laptop running XP HOme SP3 which will not acquire an IP address, either on a wired or wireless connection.
I have checked that the DHCP client is running.
I have checked TCP/IP is set to obatin an IP adress automatically.
I have removed all security software and disabled Windows Firewall.
I have removed all nework protocols and then removed devices using device manager, and reinstalled.
I have updated drivers for both NIC and wireless devices.
I have run sfc /scannow.
I have removed the hard disk and checked for viruses using multiple scans including Kaspersky.
Using the original Windows disk I have run setup and repaired the Windows installation.
None of this made any difference.
Other computers connect instantly to both wired (with the same cable) and wireless connections, so I am sure there is nothing wrong with network/router settings or functionality.
Given that it will not connect using either wired or wireless connections, I am reasonably confident that it is not a hardware issue.
In other words, I think it must be something in Windows settings somewhere, but I am at the end of my diagnostic skills.
Any help would be appreciated - but no guesses, please - only reply if you have actually encountered a similar problem and solved it.

Answer : Cannot acquire IP address

Do you have any additional security software running on the system (Symantec Endpoint Protection, or McAfee Virusscan 8.7i, or any type of Host & Network Intrusion Prevention software)?

I experienced this type of problem on a laptop that had McAfee VS8.7i and I had to disable the 'Access Protection' & 'Buffer Overflow Protection' options in order to get the laptop to receive a DHCP address.