Is the hard drive data lost?

Hello,

My friend has a Dell Inspiron 1520 running Windows XP. This morning, she tried to boot it up and got the following error:
system32\drivers\pci.sys is missing or corrupt

After googling around she found a couple of websites that suggested running the Recovery Console from the Windows XP installation CD. She attempted that, but when she pushed "R" for repair at the setup screen she got a message that no hard disks were detected. She panicked and took the laptop to a repair center, but she is scared that her hard drive data has been lost. I know you can't say whether this is the case or not, but any idea of the chances that this is some type of BIOS problem and that her data is recoverable? Any advice would be greatly appreciated.