PC stops at "Starting Windows" - HDD Failure?

In my experience this is, more often than not, a memory issue. Run Memtest86+

http://www.memtest.org/

Is it a 7200.11 ? These have a firmware issue .... the 7200.10's and 7200.12's are fine.

I have 7200.12

The BIOS settings shows the HDD Model (and also partitions and folders inside it) and RAM Model. So are they partially damaged?

use some thing like Hiran boot CD and Recreate the partitions and Try to install Via USB Thumb Drive..had a issue like this on a user PC at work, DVD Rom seemed to be the culprit

http://www.hirensbootcd.org/download/

http://download.cnet.com/Windows-7-USB-DVD-Download-Too...

I've run CHKDSK command from command prompt of System Recovery. It showed that all drives of the Hard Disk is fine..

Then I restored the system to a week back (when I had installed some windows updates) and Windows is now loading fine.  

Thanks anyways for the replies.

I'm wondering how one could have a 15day old 7200.11 when they were removed from shelves years ago? LOL

Anyways, you failed to mention WHY you opened the computer and re-connected all the wires yesterday. Just cause you were bored or what?

Did you have a problem before you opened the computer and re-connected all the wires?

Look at my post carefully. I've written 7200.12, not 11.
There was no problem with the PC before I opened it up that day except some heating issues. (Processor temp. goes up to 75C while playing heavy games). And yeah, I was bored back then and I am still learning stuffs..

I looked at your post carefully, I was talking to Jack, not you.

So you opened your pc and re-connected all the cables for no reason? That makes no sense but obviously you did something if the computer won't boot now. Lesson learned, if it aint broke, don't try to fix it. I don't see how it could be a hdd failure if it worked fine before you messed with it.

Check your heatsink is on securely and recheck all you hardrive connections, make sure the power and sata cables are secure at both ends.

75c is very hot for a i3-2100, mine never goes over 55c even in prime95 stress test. What kind of case cooling do you have? Try taking the side off the case, if that reduces the cpu temp a lot, then you need more airflow.