Windows 7 on new CPU and Motherboard help please

[Blighty Gamer]

I have recently purchased (and expect to receive in a couple of days) a new i7 4770 CPU and Gigabyte GA-H81M-D2V motherboard. My current setup is an i5 760 with a 1156 Gigabyte GA H55M S2 socket. Admittedly I know very little when it comes to motherboards and upgrading them but I understand that because I have Windows 7 Ultimate OEM currently, that is lost if I try to upgrade? The fact that it is stored on my hard drive is irrelevant?
If I put my new motherboard and CPU in and find it doesn't boot with Windows can I simply switch them back out to my old setup without issues?
If I need to get a new copy of Windows and install it, will my hard drive be wiped during setup? or will it simply 'plug and play' so to speak (i.e. it won't need to be formatted to work)?

Thanks

(P.S I hope that makes sense)

 

[Too Tall]

If you are installing a new Mobo then I would 100% do a complete fresh install.

The only issue I see you having is that when you try to install windows on the new system you might have issues with activation as its OEM.

You can legally download copies of the Win7 disks from Microsoft if that's what you mean?

 

[Blighty Gamer]

If you are installing a new Mobo then I would 100% do a complete fresh install.

The only issue I see you having is that when you try to install windows on the new system you might have issues with activation as its OEM.

You can legally download copies of the Win7 disks from Microsoft if that's what you mean?

Thanks for the reply.
So will a fresh install include formatting my hard drive?
If I have issues will I be able to replace the old processor and motherboard and revert back if needed?