i would also make sure that all connections are snug,
also,have you tried putting back the old hhd, with the original jumper settings , and booted with that ? then re-boot the computer in safe mode, when the computer loads windows ok, right click the new drive with windows xp pro on it / properties / tools tab / then click on defragment / that should do it.
then take out the original hhd, and make sure the new drive jumper's on the back of the hhd are set to master. load windows , then download the two programs :
, this program will go through your hhd and fix any errors you might have, it will also fix any errors you might have in the registry.once that's done, re-boot and see if your computer freezes.