Can I preserve my windows 7 installation?

[Beginner]

Hy ..
Please help, I have a problem
I'm not very familiar with installing os's or booting or forums
I started by reading so many posts until I began to understand nothing... And so, I decided to search from help here, from people more experienced

I had xp installed on my computer
Bought a new harddrive and connected
Formatted and installed Win seven on it (not sure how, it was a half year ago)
Until now I have dual boot option, where I can choose xp or seven
In time, xp install has become corrupted somehow, it freezes withowt any reason, nearly every hour ...
Now I want to reinstall xp in the same partition where it was (hdd 1), without loosing or needing to repair the seven installation from my second hdd
Before doing this, I disconnected the hdd and tryed to boot seprately:
-with the hdd 1 connected alone(xp install), it keeps the dual boot options, but only boot in xp, "seven" option giving error
-with the second hdd(seven installation) connected alone, I have a boot device error at powering up my computer

I have a "boot" folder, but only on my first hdd (xp installation), on the second hdd is missing. Also "ntldr", and "ntdetect"... If I will format this hdd, they will be erased...

Should I try to copy/paste these over my second hdd? If so, wich are al the folders necessary to copy? Afther that, my system will continue to boot normally, with both hdd's connected and having identical boot folders on both?

Can I do something to preserve my windows seven installation (I have important programs installed here) and dual boot option, or I need to reinstall both OS's?

Or, the third option, install a new xp in a new third hdd and manually delete the old xp system folders from the first hdd?

Thanks in advance for any advice...

 

[gregrocker]

Since XP holds the MBR for both OS's, reinstall XP to it's original HD then add Win7 back to Dual Boot menu using EasyBCD 2.0 beta.

After doing quick forum registration to use Easy beta, install along with Net Framework 2.0 needed to run it in XP.

Now Add Win7 using EasyBCD Add/Remove tab.

If this fails, boot Win7 DVD repair console or Repair CD, click through to Recovery Tools list to run Startup Repair up to 3 separate times with reboots to write MBR to Win7.

Then install EasyBCD 2.0 in 7 to Add XP to Dual Boot, accept offered boot files, Save, restart.

 

[Saltgrass]

With moving drives around, make sure the XP drive is primary in the bios.

 

[Arc]

Try to have a http://www.sevenforums.com/tutorials/681-startup-repair.html of windows 7. Previously, the windows 7 boot information was stored in xp drive, and reinstallation of xp has deleted it. So a startup repair will add the boot information.

If it does not work, Try the EasyBCD option suggested by Gregrocker. I think If you cant have access to win7 desktop, you will not be able to have a repair install.
Moreover, search for your boottime drive selection key in your motherboard screen (after power on) or PC manual. Try this key to boot in the hdd where win7 is installed, and the have the repair install.