Only 1 use for an OEM version?
Single use defeats the purpose of Windows OEM!
I have Microsoft Windows 7 Professional SP1 64 bit OEM. It is the $139.99 one at newegg:http://www.newegg.com/Product/Product.aspx?Item=N82E16832116992
I have it installed on three different computers at home and have not experienced any problems. I also build pc's for customers. I installed the OS in dozens of pc's without any problems. There have not been any problems activating after installation.
Recently I pulled a hard drive from my wife's Toshiba laptop and installed an old Kingston ssd that still had the OS from when it was installed in my personal rig last year. I popped it in the laptop and did not have any problems with activation.
I have not experienced any problems with Microsoft updates either.