Hdd_problem, help?

[MONTYX5]

Ok, I find the computer looked up in the morning and need to hard power off. Upon tring to reboot it hangs at the loading windows screen. I see that the data hdd is showing bad upon boot post. I can only very intermittently get into safe mode with it connected. Disconnected system loads and runs. On one of the remote chances of being able to start in safe mode, data hdd connected, I run chkdsk on it. Now it shows ok on boot post, but windows still hangs when it is connected. There is a lot of data on this drive that has not been backed up. Any ideas on what I should try next?
Asus P5W DH Deluxe ATX MB
Intel Core 2 Duo E6600 Processor 2.4
1-150 GB Raptor HD (os/apps)
2-400 GB Western Digital Caviar (1=data,1=backup)(400yr=model)

 

[jb_hafo]

Clean/defrag windows in safe mode?
OR, the HD is dying, do the freezer trick to get data off?
Not understanding the precise/exact error here, long time
since I've booted windows, but I always defragged before
shutdown, etc...

 

[MONTYX5]

Let me try to give a better description of what is happening.

Forgot to mention os: xp
Drive 1(d1): os/apps=1-150 GB Raptor HD (os/apps) partitioned
Drive2(d2): data=400 GB Western Digital Caviar (model=400YR)
Drive3(d3): Backup of os/part of data of d2==400 GB Western Digital Caviar (model=400YR)

When d2 is connected:
1.xp hangs at loading xp setup blue screen(not bsod). Takes awhile for hard drive activity light to go out and mouse pointer is present and responsive but nothing else.

2.On rear occasion I can get it to enter safe mode (1 in about 50 tries). F8 on start will only occasionally bring me to xp start option screen otherwise it brings me to a list of drives to boot from. When I am able to get to xp start option screen and select safe start it will actually go into safe mode on rare occasion from many attempts, usually just reverts to normal start and hangs.

3.I cannot boot from xp disc, tried 3 different disc., just reverts to load os and hangs. This happen regardless of where I select optical drive as first boot device, i.e. bios, F8 drive boot menu.

When d2 is disconnected:
1.Xp loads normally and fast

2.All the apps. that I have used so far work ok.

When d3 is connected or disconnected:
1.Makes no difference to the above actions

What I cannot understand is why the d2 drive connected would cause a problem with os loading as well as the difficulty in entering safe mode.

Also will note, that the day prior to this problem, I had downloaded the Ultimate Office7 deal. While using Office7 I needed do updates to gain a few more options, that I needed, and also at the same time I also did some xp updates (13 of them). All this required a few reboots and all seemed fine. Later that night I saved the work I had open and left it running so that I finish in the morning. This is when I found it locked up. I have been using this computer to do some work and even post these messages with no problems, d2 disconnected of course.

I am also in the middle of putting another computer together and once it is up I was planning to upgrading this one. I would just like to know that root cause of this problem. If it is the d2 drive or file corruption than that will not be a problem for the upgrade, since I was intending to go with a clean install of win7. I will also wait till the new one is up and running to try and recover the data from d2 unless there is something that can be done to repair this problem.