That's not X having the problems, but the filesystem itself. I would boot into a liveCD and use
fsck -t ext2 /dev/<partition>
where partition is whichever partition has the problem - I would guess probably your root one. If you don't know which one this is, do something like
which will list your partitions.
PS: Perhaps this is not the most tactful thing to say on Linux
Questions. But my feeling is these things don't tend to happen if you know what you're doing