Cannot start Ubuntu

[TroopaSupa]

Hello, I am new to Ubuntu and Linux and I am having the following issue:

I have been using Ubuntu for the last 3 days with no problems. Today the system froze and I rebooted the system. Once it came back it gave me the following message:

try (hd0,0)
sh: grub

____________________________

I typed root (hd0)
Chainloader +1
boot
No loaded kernel
No operating system

Can someone help me?

Thanks,

Oscar