2.6.31-14 to 2.6.31-15 Kernel Buffer I/O error

[registerkar]

Hi,
I worked on Ubuntu 9.10 32bit & had 2.6.31-14 which was amazing. It booted under 35 sec after Grub Menu. Update Manager updated it to Kernel 2.6.31-15.

On my First Boot I got an Error while Booting:

[44.850559] end_request: I/O error, dev sr0, sector 64%
[44.850506] Buffer I/O error on device sr0, Logical Block 812

[xx.xxxxxx] end_request: I/O error, dev sr0, sector 64%
[xx.xxxxxx] Buffer I/O error on device sr0, Logical Block 812

Basically [xx.xxxxxx] where value of xx.xxxxxx changes several times but the rest error is the same

Second Boot was normal but the boot time doubled to 75sec from previous 35sec & remains to 75sec always

So I booted to previous kernel 2.6.31-14 & then too I got the same error on first boot & 2nd boot onwards the boot time doubled.

Is this a Hard Disk problem?
How do I scan my HDD completely for bad sectors?
Gparted does a quit quick check & not a detailed one

& I am just 2 months in Linux...Help please...Can anyone tell me what exactly has happened?...I want the boot time back to 35 Sec

[registerkar]

well its not 64% its 6496...I actually took a snap of it & typed...I got the same error again when I removed the previous kernel 2.6.31-14 & booted again...
It starts with:
[20.xxxxxx]
[24.xxxxxx]
[28.xxxxxx]...in multiples of 4 goes to
[54.xxxxxx]
[58.xxxxxx]...

I have right now booted in Live USB mode & even now got the same error repeating 3, but this time it was
[115.xxxxxx]
[119.xxxxxx]
[123.xxxxxx]

Right now I am running Extended self-test for Hard Disk... Just to inform I have 2 HDD

[registerkar]

Well I had tried everything...
I remover previous kernel 2.6.31-14...I tested my disk...spent several hours impatiently searching for solutions & the culprit was...

A Promotional 'CD' which i had received from an Artist containing his portfolio which i had left in my DVD Drive...

Dont know how but the CD was interfering while Booting...Remove the CD & system boots Fast in 35Sec (WOW!!!) with no errors...Leave the CD in & again the Same prob...Long boot time with errors..

I am new to linux so can someone tell me out of curiosity why exactly this happened.