First BSOD, after USB booth and startup repair 'StratupRepairOffline'

He everyone,

My laptop (windows 7 on Dell XPS) decided to stop working today. When I was doing a lot of tasks at the same time it started to hang and I decided to reboot it by holding the on/off button. When it turned back on there were only two options: boot normal or repair boot. The normal booth gave a BSOD with 'unmountable_boot_volume' and the repair boot gave a desktop screen with only a moving mouse and no other options (even after waiting a number of hours). After some googling I decided to boot the computer from a USB with the Windows Repair CD mounted on it, since I did not have the CD itself. That finally worked and I was able to start the ' Startup Repair'. This gave the following problem:

Problem signature:
Problem Event Name: StartupRepairOffline
Problem Signature 01: 6.1.7600.16385
Problem Signature 02: 6.1.7600.16385
Problem Signature 03: Unknown
Problem Signature 04: -1
Problem Signature 05: ExternalMedia
Problem Signature 06: 1
Problem Signature 07: NoOsInstalled
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 1033

I have no idea what to do next. I really hope someone can help me out. It is really important for me to be able to keep my files that are on that laptop.

Thanks for the quick reply. I will try to get my hands on a repair disk, but I was wondering how that will be different from what I did with my USB. I was able to mount the repair disk to a USB and boot it from my computer. The problems started when the repair program itself was running...