Today, I accidentally swapped the hard drive on my computer while my company is in sleep mode then turn it on. After the computer restarts, I can't boot into Windows anymore. The problem is that it keeps giving me the screen where I have the option to launch system repair, but when I do that, it puts me right back to that same screen. When I select boot normally, it just goes into a restart loop.
I tried to use the hard drive on another PC as a secondary drive just so I can recover as much of the data as possible. When I do that, I can't access the users' folders which contained all the important data, but all else such as Program Files works. The error message is "Access is denied." I can't seem to be able to change the ownership of the folder to me so that I can read it either?
So are my data lost?
Have you tried error check disking the hard drive (right click the hdd on my computer and go to properties then tools) with the issue when using another hard drive? It may fix the errors that are preventing it from starting up. Also you may want to try doing a repair install through the windows install disc.
As far as the permissions problem what have you tried to do for changing the security of the users folders?
When accessing the users folder of another user even on the local operating system in Windows 7 it requires you to have permission (if you're an admnistrator it tells you it needs this special permission before continuing and then you have to click a message telling it to get that permission and continue. So it's not really a surprise that you don't have permission to do so from another os on another hdd.
Try to see if you can get it to actually give you a BSOD, that way you have some information about what is wrong. If you hit F8 just after the bios loads and get to the full boot menu, you should be able to tell it to disable automatic restart. Assuming that doesn't exist, it should allow you into safe mode and see if you can troubleshoot from there.
Definitely run CHKDSK /F /R at boot, this will verify that your drive integrity, often times I see startup related issues due to failing hard drives, because some files in your MBR (Master Boot Record) are unable to be read causing windows to be unable to start, you can do this by booting into the safe mode command prompt.
if you're not able to get the command line to load in safe mode, you'll want to notate if the safe mode boot appears to be hanging on a particular file, I often see MUP.sys, typically this indicates the file that comes after this is unable to load, and may again point to hard drive corruption / failure, if you are able to get CHKDSK to run, if you run it with /R /F arguments it should fix anything it's able to, provided the issue isn't physical.
if you still can't boot to a working command line you can always boot in under WinPE, via flash drive or CD/DVD
I always keep bootable flash drives around that I can boot into Win7PE, you can get the files for Win7PE using WAIK
http://technet.microsoft.com/en-us/library/dd349343(v=ws.10).aspx
all else fails, provided you can somehow boot to a command line, you can always try rebuilding the boot partition
"fixboot" (if XP)