OS Changing old for new and related HDD's

Hi,

I recently built a new desktop and installed Windows 8.1 on a new drive C: as the new OS. I then installed the drive C: from my old desktop as drive D:. This drive had windows XP on it so I changed the bios to only recognize C: as the OS. The problem is, drive D: has 500 gb of programs, files and data that I still want to access. Some are not a problem, some will not run and others run but won't store any new data (like games), so...

1. How do I remove the OLD OS XP on the D: drive to free up space?

2. How do I access the programs or change the pointers to Drive D: so I can access all of my old programs.

Any help would be greatly appreciated.

You can just delete the directories on the old drive as they are no longer used. I recommend backing up your data [documents, not programs] to the new drive and doing a format of the old drive to have the maximum amount of free space.

For accessing the applications, it most likely will not be possible as Windows uses the registry to point to necessary files, dlls, executables, etc for many/most programs to work. Your best bet is to reinstall any of the applications.

Your old hard drive is now being used as storage only.
Any programs installed on it will have to be reinstalled under Windows 8.1.

You can manually delete D:\Windows etc. but the best thing to do is to copy any documents etc. away from that old drive and format it to reclaim maximum amount if space, then you can start using the old drive from scratch as clean storage.