Vista Ultimate - Info: Windows failed to load

[toodles60]

Hi!

Hopefully someone can give me some advise because i know nothing about computers and mine seems to have died. My son left me a pc that has windows vista ultimate on it. There is no disk etc. This morning the pc is failing to load and i am getting the following message:


Windows failed to start. A recent hardware or software change might be the cause.

To fix the problem insert your windows installation disk and restart your pc.

If you do not have this disk contact your system admin.

File: \Windows\system32\DRIVERS\royal.sys

Status: 0xc0000221

Info: Windows failed to load because a critical system driver is missing or corrupt.



I have no idea what's happened or what to do. I tried to boot up the pc in safe mode which is the extent of my knowledge, but it won't even do that. I don't even know what a driver is, so i have no hope of figuring this out. Please tell me I don't have to reformat because I'll lose a lot of data that is irreplaceable. Am using a friends pc to find help so hopefully someone will know what to do.

Thanks for any help

Suzanna