HP Procurve 2650 has password set after factory reset

You can split a bond across the switches, but not to increase throughput. So if a server has two NICs and you plug one into each Switch, then you'll have to configure the server for some sort of bonding with failover only.

This Q/A has a lot of good details: Server-to-Switch Trunking in Procurve switch, what does this mean?

The switches have to be plugged into each other, obviously; but the single uplink to the datacenter is going to be a problem. You'll really need to get a second uplink or you'll always have a 50/50 chance of losing your connection when a switch dies (or stops working for any other reason).

A null-modem cable should work... But in this case, just reset the device to its factory settings.

To execute the factory default reset on the switch, perform these steps:

1. Simultaneously press the Reset and Clear buttons on the front of the switch with a paperclip.
2. Continue to hold the Clear button while releasing the Reset button.
3. When the Self Test LED begins to blink, release the Clear button.

The switch will then complete its self test and begin operating with its configuration restored to the factory default settings.

The switch should also obtain a DHCP address if you have a DHCP server on the network.