Cannot boot after update F11

[Vincent Onelli]

Hello,

Help! I Have 2 Computer HP laptop and Dell Desktop Both have worked fine
the laptop was getting update regularly, desktop did not. I decided to
poke around, and found the update box was not checked, so I did and then
used "su -c 'yum update'" it start the update, but at one point start to
repeat lines claiming yum was busy I left running for while then I
realize that it got in an endless loop I stop by closing the terminal.
The download continue for while, when stop I reboot but din,t even got
to the menu. I try the rescue disk but it takes me to the command line,
what I do from here? I will appreciate very much some help.
 I was ready to do new installation with F12 but I will loose important
data. This is dual boot with windows xp in 2 separate HD, windows would
not boot also.
Thank you in advance.
Vinny