|Hi Akemii, this may be the cause of your problem.|
You cannot install a WXP hard drive into another computer as a master (C:), as the operating system is configured for the hardware on the original pc.
It must be installed as a slave.
Note: if there is already a slave (and you are replacing) , make sure it is removed 'properly' by disconnecting, then booting the pc. Close the pc then install the replacement slave.
You should then be able to copy over the data files you require.
Please advise back on progress.
Good Luck - Keep us posted.