New 8.04 install fail on booting

[nepal google]

Today, my system went slower and slower and almost ground to 
a complete halt. I had Firefox loaded with 3 tabs, nothing 
special while reading the article about the new kde4 
desktop features when it happened. I also had Realplayer 
playing a radio commentary of cricket. I managed to quit 
firefox eventually and checked top to see if that had any 
clues. It showed Xorg using 75% memory.

I decided to reboot hoping to clear the problem (maybe a 
leaky memory of something like that). Now when I start 
Kubuntu 8.04 I get a fail on file system check and a 
terminal/console? is opened for me to run a manual check. I 
don't as I have no idea what to do. I just close Ctrl+D and 
the system then boots into the desktop. There is a message 
that says a log is saved at /var/log/fsck/checkfs as shown 
below.

-----------------------------------------------
Log of fsck -C3 -R -A -a 
Thu Nov 20 14:06:50 2008

fsck 1.40.8 (13-Mar-2008)
/dev/sda6 contains a file system with errors, check forced.
Error reading block 208360 (Attempt to read block from 
filesystem resulted in short read) while reading indirect 
blocks of inode 1223105.  

/dev/sda6: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
	(i.e., without -a or -p options)
fsck died with exit status 4

Thu Nov 20 14:10:00 2008
----------------

Anyone any ideas of what happened to cause this and how to 
clear this problem?

nepal.