I have an HP dv9207 laptop that came with Home Premium. I wanted fax capability, which I could have gotten in a 3rd-party program, but decided to do the "anytime upgrade" to 32-bit Ultimate anyway, just in case I might want the other features someday.
It seemed like it would be easy, so I did it. About 27 minutes into the install, or was it 27% according to the progress bar, the setup program just stopped, with no explanation. No HD access, dialog box, or anything. I didn't know what to do, so I decided to call MS Tech Support.
They told me to scrap it and start over, so I did. They also had me jump through a lot of hoops, to try this and that, and it took HOURS. I also had to uninstall Norton Internet Security, which came with the system, which is nearly impossible; it's like a virus. You have to use a tool found only at Symantec to do it.
Anyway, the 27% freeze happened again, just like before. By this time I had been on phone with MS for 6 hours. The setup just hung there, with no activity and no clues. They said they never heard of this and to just wait. Finally, the tech lady's shift ended while waiting and she said she had to go home. She was filing a report for the next shift when, after waiting about an hour, the setup mysteriously resumed, and finished successfully within a half hour.
Would I do it again? HELL, NO!!!
Since then, about 10 months ago, the system has been "OK". I have used Fax and Scan, but no other Ultimate features. I maxxed out my laptop's RAM at 2gb, but wish I could have 4gb, because it's very slow and uses up all the memory constantly. I get a BSOD at least once a week. And the "Ultimate Extras" are vaporware.
If you are intent on uprading Windows, I highly recommend poster # 16's suggestion to switch to XP Media Center Edition, which you can get from Newegg for less than the Ultimate upgrade. XP MCE is built on XP Pro, so it really is the "Ultimate" XP. I estimate your machine will be 2 to 4 times as fast, more stable and compatible, and use a whole lot less RAM.
But be prepared for a lot of work, making sure you get drivers for all your devices. I've been planning this "upgrade" myself, researching it a lot, and in the most thorough description of the process I've found, the user took 2 weeks to get his system working completely. It took him that long to find a driver for his microphone.
Having found out this stuff the hard way, I hope this will save anyone who reads this a LOT of trouble!