I have a dell computer SERIES E with a 40 GB maxter hardrive and I just got a new dell computer with a burner in it and everything. I tryied to put the hardrive from the series E to the computer with the burner and it says I have to activate windows on it and then it says product activation but on the other computer the drive is already activated. Is their a way to find the product activation on the hardrive and activate it on the other computer?because I know you can activate it online and by phone but I'm not sure if it costs money for an activation code any help would be helpful THANK youI'm suprised it even booted that far ...moving a HDD from one machine to another with any Windows product XP or newer is a crapshoot at best,,,
MS's policy is one copy one machine.

Did you buy a new machine without an OS installed ? ?

I don't quite understand why you would need a previously installed OS on a brand new machine...

At any rate contact Microsoft and ask them. It's possible they will re-activate you.You most likely were able to get this far because they are both Dells. Sorry to say, but you're going to have to buy a new Operating System. Or, you could research the subject. Well I have 2 Hardrives from 2 diffrent computers. I have a 20GB seagate and a 40GB maxter. I got the computers from work and I had the 40GB one first in my first dell computer but the case was too small. So then I got the second computer and it had a 20GB hardrive and a burner in it bigger tower. So then I tryied putting the 40GB one in as my Master and the 20GB as my slave into another case and it said that I needed to activate it. The thing is I have no IDEA why its telling me to activate it because both hardrives when they were in seprate computers worked and were activated. Now I tryied switching the 20GB as my master and the 40Gb hardrive as my slave but my 40 has all my burning nero software on it and I'm finding it hard to get it to my 20GB hardrives desktop so that I can use it so I'm trying to actiave the 40 to use that as my master I will try contacting somone but if anyone could tell me how to find the activation code posibbly in a file somwhere that I could use in the computer?Ok ok. You set your 20GB as your master in the "new" computer. Because this was the original state. They are both Dells, this is why the MB is even reading that other HDD and booting the OS. It's asking you for a key because it's trying to read the OS from that new HDD. You need to set the 20GB as your master. That's the only way your going to get out of having to purchase a new OS unless you have Ghost or something to re image that "new" HDD. Then you can image your other HDD and run the OS from it. Make sense? Basically, the OS knows that the HDD didn't come from that computer and it wants you to activate it.

Even if you find the activation code your not going to be able to activate it. It knows the original computer that it came from. It's a one time deal. One OS, one computer.

About your software that you are trying to keep. There is no easy way to go about this. You are going to have to have some IT knowledge in what kind of software can help you transfer this stuff. It's almost impossible. The OS on the 20GB HDD is not going to be able to read that software on the 40GB because of registry settings an all of that. Do you have the original CD's for that software?

If you are talking about calling a computer store to help you, I would save your money. They aren't going to be able to do anything for you. If anything, they will try and sell you new stuff with an OS and tell you it's all ok. On the upside, you have more space now! It is asking for activation because the hardware has been changed...i explained this above.
XP installs are tied directly to th hardware the OS is installed on.
If you changed the MBoard and CPU it would be doing the same thing.
When you contact MS you can say you had to replace the MBoard...if you say you are moving from one machine to another they will want to seperate you from your money...
This is the only option if you do not have an XP CD with a Activation key period.

rasilun,
An image still wouldn't work as it contains the same info that is on the HDD now including the HAL info
Just so you know...I THINK you misunderstood me about the imaging.

And yes, you can give MS a call to get another key if you word things the correct way. But, this isn't something you NORMALLY come out and tell people. So, I didn't...

Anywho, cheers!I don't misundestand you about the imaging...it simply won't work as you stated...
Any doubts try it in this scenario and see...