Win 7 Ultimate from old computer onto new computer?

About a year ago I bought Win 7 Ultimate and slapped it on my outdated HP a6200n w/ 1GB sapphire 4670 vid card. Anyways over next couple weeks I am ordering bits in pieces for a completely new comp (FX 8150, 1 GB Sapphire 6850, 8 GB RAM [but 16 GB later]), but I'm curious how I need to install Win7.

I plan on yanking my 500 GB from my old comp that I installed Win7 Ultimate on a year ago and using it on the new computer. I've looked around and looks like it will cause problems if I try to use that installation on a completely new computer, so I will need to re-install windows. My question is when I get all the pieces together what would be the best method for me to re-install windows?

Also, will I have problems activating my Win 7 Ultimate onto this new computer since I had already installed/activated it on my old one, even though the old one will no longer have windows 7 as its hard drive will be in the new one? Is it even allowed? I'm pushing my budget pretty hard already with this new comp, I really rather not wait another week or two to buy another operating system.

Probably be fine.

The activation servers get alarmed if you do it too often.

Another machine after 12 months shouldn't cause any issues.

Thanks for the welcome and fast reply.

I should of mentioned I have Win 7 Ultimate Upgrade, not retail. Didnt pay attention when I bought it, saw the cheaper price, got excited and went for it lol.

I've already backed up all my vital data. I partitioned 80 GB for the Win 7 installation originally, when I format, will I have to recreate the partition again?

In the event I have a problem with activation, what do I need to straighten it out. I still have the original box/case with the key ofcourse, but not the receipt from the purchase.

The upgrade works as well as the full version. But is it retail? If not, you will likely have activation problems if you change motherboards.

If you do a clean install, you can keep existing partitions, but there is no particular reason to do so. You can delete all partitions during the install and Windows will then create new partitions.

If you get in an activation jam, you can usually sort it out without a phone call via the automated process. In rare instances, you will have to call in.

Bought it from Best Buy. It says "Upgrade - Designed for Windows Vista*" on the top left of Box, so I assume that means Upgrade, not Retail or OEM.

"Upgrade" and "retail" are not mutually exclusive terms.

I bought my Windows 7 upgrade disk at Newegg. It does not say retail anywhere on it, but is in fact a "retail" copy.

It installed fine to a brand new empty drive. The legal requirement for an "upgrade" disk is that you own a qualifying OS already, such as Vista. I did. But the Vista disk does NOT have to be installed--you just have to have a legit copy. You are not asked to enter the Vista disk into a drive or provide the Vista Product Key.

I'd assume you are OK if your disc does NOT say OEM.

Do you have a retail copy of XP or Vista which will qualify you to use Upgrade version on the new computer? It doesn't need to be installed but just kept on hand and not used. If not you may want to consider Builder's OEM which has a price break.

However when you boot the installer it will see an OS on the HD and allow you to use the Upgrade key up front anyway with out having to do the workaround it the tutorial Pauly provided - which shows how to activate Upgrade version key on new or wiped HD.

As Doc suggests you can also SysPrep to move HD to another computer
without reinstalling at all. But you will have to reactivate and do the workaround in option three in Clean Install with a Upgrade Windows 7 Version