Purchased 64 OEM by accident. Do I eat my mistake?

I did not install it becase it would not insall on my 32 bit machine, How can I make this right. Can anything be done to make my computer work without having to buy entirely new license even thought I did open the pack, but failed at instaling? This is my first build, and I did not know that my machine was not capable of 64 bit mode, or that I could not exchange it after Opening it. I dont have money in my budget to buy an additional os at full price. I know that Microsoft offers deals for OS upgrades if you already own a license from an earlier os,,,, If I Register my copy of windows 7 64, can I "downrgrade" to 32 without paying fullprice because do own a os liscence? Can anything be done because this
was an honest,and huge mistake?

You'd have to contact Microsoft and tell them of the situation. I could see them possibly canceling your current activation key and supplying you with a new one. You might have to pay a small fee for them to ship a 32 bit DVD to you or they might actually supply a download link.

In any case, Microsoft would be the only ones able to help if the retailer refuses.

Anyhow, you say this is a "build" so I'd have to assume that means new. Any computer built with any components and cpu recent at all is going to be 64 bit capable.

Do you know which exact motherboard and cpu you have?

If you really need the 32-bit version then go to this link: Windows 7 ISO – Official Direct Download Links

Only Home Premium and Professional are available from Digital River for an ISO image download though. Ultimate links died several months ago.

Download the ISO image you need and you ImgBurn to burn it to a DVD blank disc at no faster than 8x burning speed. Then use the verify function to make sure it was a good burn.

YOU CAN USE THE SAME KEY!

Like Nibs said, all you need is the disk. A downloaded burned 32-bit copy of the exact same version as you bought. You can even barrow a copy from a friend (although if you can burn a copy for your self I would, just so you have it). Then use your product key and activate.

And no you cannot downgrade from 64-bit to 32-bit nor visa versa - simply install the correct version, in your case 32-bit but use the key you bought and paid for already.

I will repeat so it's clear, if your disk is 64-bit Home Premium then you must install the 32-bit version of Home Premium for it to work; if you bought Professional then you need 32-bit Professional, etc.

Do NOT activate the 64bit version nor try the key on a different computer as it should become locked/attached to that build (for at least 90 days). Install the 32bit version on the computer you plan to use it on and only activate that version.

What about my situation? I do have Windows 7 professional and when installing a CAD app that is in 64 bit and they tell me to install the 32 bit version of the app? I desire it to be 64 bit version of the app. What do I do with my windows 7 professional?

The 64 bit version of the app will only work on 64 bit Windows.

Install the 32 bit version of the app - OR - Install Windows 64 bit and then install 64 bit app.

Download the 64-bit version of Windows 7 Pro from here: Windows 7 ISO – Official Direct Download Links

Save the ISO image and then burn it to a blank DVD with ImgBurn burning software.

Get ImgBurn at: www.imgburn.com

Burn no faster than 4X speed and use the verify feature to make sure the burn went okay.

You CAN use the same key that you used for the 32-bit Windows 7 Pro.

Or use XP virtual mode. You are entitled to one license, assuming your PC has enough grunt.

CAD apps need all the horsepower they can get, which is why I'm assuming he would like to install 64.

Who is "they" that tell you to run 32-bit? If your computer can handle 64-bit and your software works in 64-bit then I would not consider 32-bit and if the software IS 64-bit then it won't work any other way.

The only time I would recommend 32-bit is if your computer cannot handle it or if you require the use of hardware which cannot run under 64-bit or if you use so much old 16-bit software, which is impossible to run in native 64-bit, that an alternative such as virtual mode is impractical.

Note: software designed for 32-bit may run slightly slower under 64-bit so if there are two versions it is best to run the version for your OS bit-size.