I have been running Windows 7 RC1 since it was available a couple of months ago and had no issues whatsoever until today. When I start my laptop, Windows does not boot but instead Windows System Recovery starts. I've used diskpart to list the partitions on the drive and my system partition (c:) has a RAW filesystem. I really need to save all data on the disk as fast as I cant and I would really like not to have to reinstall my system.
Assuming its not a disk failure of some flavour (in which case you're out of luck), i'd suggest making an image of the disk with dd, or some rescue oriented version of it before you do anything else, just in case.
With that out of the way this sounds like the sort of thing testdisk excels at - run an analysis from it, and if your old partition is detected, you should be able to restore your partition.
I've been trough this trouble too, when i tried installing Hackintosh together with Windows 7 RC1.
There COULD be a new partition called 'System Recovery' or so...?
Check that, there should be some boot files, put them into the Windows 7 directory.
You can do that with stuff like the CMD from the Win7 Disk.
Now try to boot, you should come up into the Windows Boot Manager. It will probably tell you something about the boot isnt valid.
Now insert your Windows 7 Disk, Go to system repair, and system boot repair or so. It MIGHT happen that when you need to select the OS, there is nothing. Just continue.
This should work, however try to be carefull. I personnaly would recommanded a clean install on a new partition and then copying files etc but like you said you did not want that... --> then just get a Windows 7 original copy, no RC.