Regards the downloads - x86 & x64? I've heard of 32bit & 64bit, but 84bit? I haven't heard of this. Mine is 64bit however.
I can definitely understand your confusion at the 32-bit and 64-bit naming conventions. Here's how it works: Intel and AMD processors use Intel's x86 instruction set. As Intel has evolved its instruction set, it has created various revisions which are (almost) all backwards-compatible. For example, i386 is the 32-bit instruction set that debuted with the Intel 8086 processor, i686 is the 32-bit instruction set that debuted with the Intel Pentium Pro processor, and AMD64 (or x86-64) is the 64-bit instruction set that debuted with the AMD Athlon 64 processor. Code compiled for the i386 instruction set can be run on processors that support the i386, i686, or AMD64 instruction set, while code compiled for the i686 instruction set can be run on processors that support the i686 or AMD64 instruction set, but not i386. Since 32-bit Intel processors are by far the most prevalent processors using the x86 architecture, x86 is commonly used to refer to the i686 instruction set architecture. However, since 64-bit programs cannot be run on any 32-bit x86 processor, x86-64 needs to be differentiated. For convenience it is commonly abbreviated x64.
I've also heard of retail & OEM versions. I don't actually know what version of Win7 i have installed in my laptop. I do however know it's "Windows 7 Pro OA for Lenovo Singamore" which it states under the battery.
Since your laptop came from a major system manufacturer, it shipped with an OEM version of Windows. (OEM stands for Original Equipment Manufacturer.)
Also the model is 2481-2TG if it makes much difference.
I would prefer a clean install but xorangekiller makes a good point about the Lenovo Utilities (i wonder if these can be downloaded/installed after a clean install?)
The ThinkVantage System Update utility that I mentioned earlier can download and install any of the Lenovo utilities that you choose, even after a clean install. You can also download the packages and install them independently from the driver downloads page for your machine on Lenovo's website if you choose.
Also, regarding your link xorangekiller, thanks, but i don't actually understand it. I'm very novice at this. It sounds like a good idea - not having to manually activate, but i don't understand how you're doing it, even with your link.
Fortunately if you use the utility I attached to the aforementioned post, you don't really have to completely understand how it works. Simply follow my instructions to download it and run it. If you would like a simpler explanation of how my utility works, let me know and I would be happy to explain it again.
I can understand how some people might be worried about the "don't understand it, just run it" advice. I admit, that sounds a little suspicious. Most of the utility is implemented in Batch scripts, which anyone can open with Notepad and view, and I would be happy to provide the source code for anything else in the package that I wrote. Basically, everything in the utility can be accomplished using utilities included in Windows since this is an official Microsoft procedure; I merely automated it.
So would i be looking for OEM/retail download & are the above links OEM/retail? I assume i'll be requiring the x64 rather than x86.
The ISO that you will be downloading (whether it be the one that ashpowell linked to or another official Windows 7 installation disc) will accept both OEM and Retail product keys. Microsoft used to have separate discs for each key type for Windows XP and earlier, but starting with Windows Vista any installation disc may be used with any product key, provided it is for the right edition of Windows. Similarly, starting with Windows Vista product keys may be used with either the 32-bit or 64-bit version of Windows so long as the edition is the same. For example, you may use your Windows 7 Home Premium product key to activate either Windows 7 Home Premium 32-bit or Windows 7 Home Premium 64-bit.
I definitely recommend installing the 64-bit version of Windows. So long as your processor supports x86-64, I see no good reason for installing 32-bit Windows in 2012. The security enhancements alone make 64-bit Windows superior, not to mention the other advantages.