Who made the NEW drive? If it is Seagate or Maxtor or WD, you can download free software for this job. Other makers MAY have it also. The task is called cloning - you want to copy absolutely EVERYTHING from the old drive to the new one so that the new one can completely take over the C: boot drive functions. But probably, during this process, you want the new C: drive to be much larger, also.
Seagate's website has a utility package called Disk Wizard. It is actually a customized version of Acronis True Image which is capable of doing a lot of useful stuff, so be sure to get the manual and read it. Part of the customization is that it can make clones only TO a Seagate drive, or to Maxtor (owned by Seagate). Similarly, WD has a package called Acronis True Image WD Edition if you are making a clone TO a WD drive unit.
In making the clone, watch for a few details. First thing is to be VERY sure you designate the NEW unit as the DESTINATION drive, because the destination drive's old data will all be destroyed! Next is size. By default these packages tend to set the size of the Partition on the new drive the same as the size of the old drive, leaving a lot of empty Unallocated Space on the new drive for creation of additional Partitions later. But many people want the entire new drive to be one large Partition to be used as the C: drive. You can set it this way manually, just look for how - don't accept the defaults blindly. If your old drive had more than one Partition on it, the default new layout also may not be what you want, and you should manually set the several Partitions as you would prefer. You probably want the new unit to be bootable so you can boot from it and use it as the C: drive, and that will be the default. For moving to a larger drive you often will want the new one to be Formatted with the NTFS File System, even if the old one was FAT32, so just check that setting.
You already have installed and formatted your new HDD. As it turns out, the cloning software would have done all that for you, and will basically re-do it as it sets the drive up to receive the clone copy.
One small item that may or may not affect you is the size of the new drive. Some people with older systems and small HDD's have an issue with what is known as "48-bit LBA Support". This feature is necessary to use an HDD over 137 GB. It is needed in the HDD itself (obviously will be there in a drive this big), in the HDD controller, and in the OS. All SATA systems and controllers have this feature, but you are using an EIDE system, so maybe you need to check that. On the OS side, Windows XP in its original form did NOT have this built in. If your OS on the old system is that, you really should update it BEFORE making the change. But if your Win XP already has been updated to Service Pack 1 or later, OR if you are using Vista or Win 7, there is no problem.