You will have to reinstall each and every program if you format. That's just a fact of life with Windows.
On the up side, during the reinstallation process for Windows, you can easily merge the partitions on the main drive, though you'll lose any data on the "D" partition in the process, so back that up beforehand. I'd also recommend making a SP2 slipstreamed installation CD for Windows. Saves time later on. Use Google if unsure on how to do this.
I own a Sony VAIO PC that is about 5 years old. It is a Pentium 4 1.8 gz machine with max 512 mg ram. Back then they partitioned the hardrive alloting 15 gb to C and the remainder of 60 gb to the D drive. That really didn't bother me then but the C portion of the drive has loaded up to about 96 % of it's capacity. About 2 years ago I purchased an external USB drive, 200gb now allotted the E drive. To further complicate my issue I installed XP's SP2 about 18 months ago and it almost wiped out many of my top applications in the process. I took SP2 off my pc and I'm still running SP1.
I want to begin anew with a new larger internal C drive and install Windows XP Professional. How can I move applications that reside on the C and D drives to the external E Drive and then set up my new internal as the new C and reformat the C/D drive as extra disc space. All of my software is legitimate and paid for however I have purchased upgrades to some of my main programs like Adobe PhotoShop and my web authoring software. Is there any clearcut, clean method of migrating apps to other drives on the same system? Also do have any suggestions on how this can be done? I am very desparate for help.