Windows 7 installing on D: rather than C:

I've never heard of not being able to reinstall the native OS which came with a PC because of the size of the HD. You're entitled to reinstall that XP for the life of the machine no matter what hardware changes, except for the mobo.

You don't mention if or where the Ultimate Upgrade you bought is currently installed - are we supposed to guess this? Unless it is currently being used on another PC you most definitely can move it wherever you want as long as there is a qualifying copy of XP or Vista involved - though it doesn't have to be installed.

A new quirk in this still not resolved issue. I install the video recommended which is the "Mobile Internet (R) 915GM/GMS, 910 GML Express Chipset Family". It installs fine- TWICE. Not sure why here are two listed but there they are.

This is not uncommon. How is performance? That is a very old chipset, but it will run Win7 - without Aero.

OK, Microsoft says that the disk I was using was for upgrading from another version ONLY, even though the "clean install" option is available. So, I plunked down the cash to get the full retail version of Windows 7 Home Premium, and I am now having a whole host of problems I did not have before, mostly in the network devices and drivers category. The Broadcom 4450x NIC seems to install just fine, with no extra drivers needed, but the Network and Sharing center has a red x on it and iknsists there are no connections, which did not happen with the Ultimate installation, and there are a whole list of things under network that show as not installed properly, plus the System Event Notification Service service is not running and the Event Log is not running either. This is the most difficult installation of a Windows product I have ever done.

If Vista or XP came with the PC, or you have another copy of either which you don't intend to use, then you can indeed use Upgrade version on the PC - whether the qualifying OS is installed or not: Clean Install with a Upgrade Windows 7 Version.

Read over carefully the Best Practices for getting a perfect Win7 Clean Reinstall - Factory OEM Windows 7 which are the same for retail. Did you follow the steps given for drivers to wait until all optional and Important Windows Updates are installed before importing any? Did you put your network driver on disk or stick so you could get online to do all Updates first?

Once you've done these things which were referred to you earlier, installed to a wiped HD as given in earlier steps, if you then have any drivers or functionality missing post back a screenshot of your Device Manager showing the devices in error, or which shows the missing functionality if possible along with a full description, and we will help you complete it successfully as we have for thousands of others.

Hold off also on installing programs until all Updates and drivers are done (with our help if necessary) because losing System functionality like that with a known-good installer on a wiped HD can really only be caused by something you're installing. If necessary we will look over your list of Programs to install to see if we spot anything problematic.

The tools and methods which assure getting a keeping a perfect reinstall are all given in Clean Reinstall - Factory OEM Windows 7

A few problems with this answer which I have already outlined in previous posts but I will mention them again. I only do this because I am tired of reading the same solutions that DO NOT WORK (emphasis, not shouting).
The laptop did indeed come with Windows XP. The hard drive crashed about 3 weeks ago. I located a supposedly comatible drive through Dell, and ordered it. It didn't come after 2 weeks, so I called them to find out what the problem was. Answer: the drive was at end of life, and they couldn't get it. I was really stymied, then suddenly the drive shows up.
So, this was NOT the original equipment in the laptop, though it was supposedly compatible. However, I decided to go ahead and re-install the OS that came with the laptop, Windows media Center Edition 2005. This should have worked, but unfortunately, that version of XP did not support a 320 GB HDD, so there was no way to install XP and upgrade it as I had hoped. I then decided to use the Windows 7 Ultimate upgrade disk that I had gotten for my PC, knowing full well that I would have to buy a second license, but I figured that I could at least install 7. WRONG! Every install I did, after doing as you suggested and installing all the updates, I was taken to the "Startup Repair" screen, at which point I had to try using System Restore, which sometimes worked but most times didn't. I finally decided to call Microsoft and explain the problem. Their answer? The software I had would NOT work for installing a full copy of the software, it would ONLY upgrade (or replace) aan existing OS. With that, I decided to pick up a fresh retail copy of 7 Home Premium, and attempt to restore the laptop using that. This has been even more frustrating, as at almost every step I have had problems. I found and downloaded all the drivers necessary, and they seemed to work for a while, but every time I allowed Windows to install more than one or two updates, back to Startup Repair I would go. I have been unable to find any actual problems with either the OS or the laptop, but an installation of Windows 7 will not remain stable for more than a few restarts. Sorry if you find any of this offensive, but I have read through your "7 Clean Install - Factory OEM Windows 7" and it simply does not work in this situation. I an't install all the necessary updates, because the laptop ends up in Startup Repair mode after the first few of the over 100 necessary updates. I need to install the network driver to go online to do the updates, and all the others install fine, but the thing still craps out after working erfectly for a half hour. Not sure what the problem is, but I seem to have spent well over $300 for no apparent reason.
Here is the latest "Problem Details" from Startup Repair:
Problem Event name: Startup Repair Offline
Problem Signature 01: 6.1.7600.16385
Problem Signature 02: 6.1.7600.16385
Problem Signature 03: unknown
Problem Signature 04: 21199937
Problem Signature 05: AutoFailover
Problem Signature 06: 2
Problem Signature 07: CorruptFile
OS Version: 6.1.7601.2.1.0.256.1
Locale ID: 1033

and by the way it's not a "reinstall" it's a new install, which I have also outlined in previous messages.

This is really mysterious since installing with a known-good installer on a wiped HD where no bad or infected code could remain should not present those types of issues unless some rogue program is messing up the install.

It would be good once you get online to test it for awhile without installing anything to see if these problems are present.

Then if you can't get online make sure the network driver you use to connect is installed. If your network doesn't show up in bottom-right System Tray then rightclick to Troubleshoot, report back findings.

Once online do all Important and Optional Windows Updates then test it again to see if there are any problems. If not install the drivers missing in Device Manager and test it again.

Report back what happens to this point before beginning to install any programs.