Kernel Upgrade Problem in Feisty

[das]

Hello Friends

Till last night my machine was working pretty well with kernel
2.6.17-11-generic. Today morning after update, another kernel was added
there: 2.6.20-14-generic. 

But, the problem is, after that even the 2.6.17-11-generic kernel is not
working too, neither the new one. I am booting with the even older
2.6.17-10-generic kernel. 

After deleting the 'quiet splash' part in the kernel details, the boot
message is showing  that the latest kernel 2.6.20-14-generic is stopping
after reporting my combo-dvd drive of the laptop. And the
2.6.17-11-generic kernel which was working quite fine till last night,
is stopping there after mounting the root file system, the message is
something like "Waiting for the root file system ...", though the
earlier line showed that the root file system is mounted. The HD is a 40
GB sata, the partitions are getting read as '/dev/hda<?> by the
2.6.17-10-generic kernel, while they are getting read as '/dev/sda<?>'
by the 2.6.17-11-generic kernel. 

Any help?

---
das