WinXP PC reboots on cmd

[Cy6erpuke]

I have bought 2 brand new PC's. I am setting up a home network but I cannot check their IP addresses, because when I enter the command prompt, either through Run: cmd or trough start > programs > accessories > command prompt..... the PC's reboot! I cannot do anything in command prompt, because the PCs both reboot immediately.

Please help. I am getting no help from Microsoft or PC manufacturer.

I have deactivated the reboot on error option (system recovery). Still reboots, no error message. It is almost asif the command prompt command is linked to a reboot command.....?