Recover ESXi 5 Install - USB Failure

Hi guys,

I have ESXi installed on my HP Microserver N40L. I installed the OS on a USB stick, and all the VMDK files etc are on the HDD that came with the Server.

Today we lost power in the house and I think this has corrupted my USB stick that ESXi was installed on. Now when I boot the server I get a:

Loading /v s00

Fatal Error 6 (Buffer too small)

I managed to get ESX back after a few reboots, but now it seems i've lost it completely.

Assuming my HDD with all the VMDK files are still in tact, what is the easiest way for me to get the OS back?

Apologies for the newb question

Thanks

Luke