PS/2 and all USB ports are not working

I have a eMachine T1840 (XP SP2) and after a power supply failure, the PS/2 and all USB ports stopped working even after replacing the power supply. It just keep giving me the “Power Surge on hub port” error message.

Device Manager can see the USB hubs and the USB mouse can draw power from it (light on optical mouse), but it’s not working. The PS/2 mouse cannot be detected by the system at all.

What options do I have besides replacing the computer entirely? Would it work if I buy a PCI USB card?

Thank you!