Help: system's screwed up after updating

[athlete]

I'm using FC10.
Also have win xp

last night i updated the system(using update system). and after restarting the system was not ready to start(black screen with a cursor blinking). then i put in the CD and chose the upgrade system option but in vain. then i put in the FC11 CD and chose the upgrade option. in between the setup due to power failure it was interrupted. later after resuming the upgradation it wasn't upgrading but started a new installation.
I used some programs viz., ext2fsd and similar stuff(to recover data) but neither has a proper usage guide or may be something has gone wrong in linux partitions.

1. i have no backup. hence i want the data lying on those partitions
2. can the system still be reinstated to the previous form
3. has the problem(black screen) appeared due upgradation of the kernel and its conflict with old graphics drivers
4. what should i do.

[reed9]

First thing, I would boot up a live cd and see if you can access the data on your partitions, then back it up to an external drive.

Afterwards, I'd do a fresh install.