Accessing Files From Secondary Hard Drive.

I am using Windows XP and have two hard drives. Until recently I had Windows installed on one hard drive and all my important files (photos, business files, videos, etc) were also on this drive. My other hard drive was completely empty. Suddenly I started encountering problems with Windows and while I was using Windows it would completely freeze. I would pull the plug on the computer and start it again and then it would be fine - for a few hours - and then it would freeze again. The problem started happening more often and more quickly after rebooting and interestingly I noticed over the course of a few days that the problem seemed to be worse whenever my heater was turned on. I left the heater turned off and didn't encounter a problem again for a couple of days, but then it started happening again and more often even while the heater was turned off. I figured because there seemed to be a correlation with the heater being on and the computer's performance that the fans or the power supply inside the computer were over-clogged with dust. I opened up the computer and thoroughly cleaned out all the dust I was able to and made sure all the fans were dust-free. It didn't help. The computer's condition continued to deteriorate and occasionally when I attempted to re-boot the computer it would completely freeze before getting to the Windows boot screen or it would display the following message.

Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware. Please check the Windows documentation about hardware disk configuration and your hardware reference manuals for additional information. Over the next couple of days the computer wouldn't get to the Windows loading screen at all and it would only boot to the point of displaying the aforementioned message.I took my computer to my friend's house to see if he could fix it. He said that some of the boot.ini files in my version of Windows were damaged or I had accidentally deleted them somehow. Because I was completely unable to load Windows there was no way to do a System Restore so he came up with an alternative plan. He decided to load a new Windows XP onto my other hard drive and use that drive as my master. He said even though Windows was loaded onto the first drive, I would be able to access the files from it with the new Windows in Windows Explorer. So he did it but then we encountered a new problem. The new Windows works fine but for some reason I am unable to access the files from the other hard drive. I think this is because my original Windows had a password on it. When I used to load Windows you had to type a password to login as me and access my files. Otherwise you could only be a guest. But now when I try to access these files an Error message comes up saying these files cannot be accessed. It doesn't even give me the option to type a password.So basically what I want to know is this: Am I able to recover these files from my original hard drive. I really need them for my business and I have five years of family photos on there that are of high sentimental value to me.