I've solved the problem. Figuring out what I had done helped alot.
I remember that I was thinking about changing to GRUB yesterday, but changed my mind. Anyway I had already run the command to install GRUB (or so I thought), so I just did a LILO -v to skip it.
Now I realized that I must have run `grub-install /dev/hdc[b]1]/b]` instead of `grub-install /dev/hdc` and as a result of not knowing what I did I replaced the boot sector of the Windows partision with GRUB.
To answer rberry88's questions: This resulted in nothing at first when I were just jumping between differen kernels yesterday (yes, I kept my old kernel), but when I today were going to start Windows to pay my rent (as my bank doesn't support Linux

) I got into GRUB. grub had the option to boot my kernels and Windows, but the option Windows just started GRUB again, and I could keep that loop on for infinity. Booting linux from GRUB worked just fine, so I got here and posted for help. Well, actually first I tried to boot by CD rom and SYS c: but it wouldn't recognize the file system.
As I did want to fix this problem as sson as possible I tried to find any help already available on it, and finaly I found
this page after half an hour.
So I did
dd if=/dev/zero of=/dev/hdc1 bs=512 count=1
booted from the CD again, and then did
sys a: c:
And it all worked.