OEM windows 7..what changes can i make to my pc

You can make just about any change except for the motherboard. You can replace the motherboard with the same (or equivalent) but you are not allowed to upgrade it.

hey thanks for the help

You are correct that you can only install it on one system. However the legal wording is one system at a time. You can make any changes you want to your pc and reinstall the same windows back onto it. As long as you don't install it on multiple systems at once.

Example:

My old gaming pc had windows 7 64bit. I also had a windows 7 32bit laying around(accidental purchase). A few months ago I build myself a new gaming pc and my old one has been turned into a HTPC. Since I wanted my new gaming pc to run at 64bit I formated my old pc and put the unused 32 bit win7 on it. Then I installed the 64 bit on my new gaming pc.

I had no problems what so ever. The old pc was an athlon X4 and the new pc is an i7 950.

I had a problem way back with winXP. Microsoft tracks how many times a licence key is used. If you use it too many times they will not authenticate your windows with an overused licence key. But just call them up explain the situation and they will re-allow your licence key.

I'm afraid that what you say just isn't true. OEM versions of Windows are tied to one computer and cannot be moved to a new one. This is different to the situation with a retail copy of Windows.

And, as I said, you cannot (in theory at any rate) upgrade the motherboard. (But there's nothing to stop you phoning Microsoft and trying to convince them.)

Here's what Microsoft say on the subject:

"The OEM software is licensed with the computer system on which it was originally installed and is tied to that original machine. OEM licenses are single-use licenses that cannot be installed on more than one computer system, even if the original machine is no longer in use. The End User Software License Terms, which the end user must accept before using the software, states that the license may not be shared, transferred to, or used concurrently on different computers."

and

"Generally, an end user can upgrade or replace all of the hardware components on a computer—except the motherboard—and still retain the license for the original Microsoft OEM operating system software. If the motherboard is upgraded or replaced for reasons other than a defect, then a new computer has been created. Microsoft OEM operating system software cannot be transferred to the new computer, and the license of new operating system software is required. If the motherboard is replaced because it is defective, you do not need to acquire a new operating system license for the PC as long as the replacement motherboard is the same make/model or the same manufacturer's replacement/equivalent, as defined by the manufacturer's warranty."

Actaully, despite what MS say, if you have an OEM version of windows it is locked to that system's brand of motherboard, not the model. It does this by verifying the manufacturer name in the BIOS. MS would prefer you not to install it on a different motherboard as you have "created a new computer" and would prefer that you purchase a new copy of windows for that "new computer", but they cannot and do not enforce this.

Personally I have successfully installed the OEM windows 7 that came with an HP Desktop on an old HP Laptop, and the OEM Windows Vista that came with a Dell Laptop on a Dell Desktop with no problems, and they have very different motherboards.

There are a large number of OEM versions of windows, for example HP, Dell, Sony. There are also various Motherboard manufacturer OEM versions eg Asus, GIGABYTE etc.

So for example, if you have the DELL OEM version of windows 7, you can install it on any DELL machine, not just the one that it came with.

If you have the Asus OEM version you can install it on any Asus motherboard.

There is no limit to the number of times you can reinstall or the number of different machines you can install on (provided they match your OEM version). However, when you reinstall you have to "Activate" Windows again. If MS find you with more than one copy of windows running and "Activated" with the same serial at the same time then they may disable your serial and you won't be able to get updates.

I have been running 2 machines on the same activated OEM serial and been able to get updates for several months without any problems, but there's a risk in doing this that MS will detect me abusing my license and disable it, so I cannot really recommend it...

You can defeat the BIOS brand check with a reasonably simple hack, and the Activation checks are defeated quite easily with the DAZ loader, but doing either of these means your system is theoretically not supported by MS, warranty voided etc.

That would explain why it worked for me. It was moved from asus m2n68-am to asus sabertooth x58