I see the boot flag is still on the new drive. That could very well be a issue. But can be fixed with the XP CD. At this point i would suggest a restart. If XP doesnt come up, which i suspect it wont cause of where the boot flag is, put the XP CD in and go to the Recovery Console.
Load up the XP CD till you get to the first set of options. There you will see Press "R" to get to the Recovery Console. Choose that. When you get in you will be prompted to select you XP install. Should be opton 1. Type in 1 and enter. It may ask for your password if you set one up.
From there after you get to the C:\ prompt use these commands:
Then restart. That should get you back into XP. From there if you are going to install Vista restart with the Vistqa DVD in and go for that install. If i am seeing this correctly you have Vista already installed get EasyBCD from NeoSmart.net and install it. will require .NET 2.0 to be installed.
From there add a entry for Vista.
Windows Vista - NeoSmart Technologies Wiki
Detailed instructions there if needed.