Pandora92
plus technically you then need to factor in the cost of another copy of Windows since I doubt the average laptop user would plan on installing Linux (I'm presuming the copy of 7 that it comes with is an OEM version valid for one install only). :|
The license is tied to the machine (generally defined as motherboard) not the number of installs. You could reinstall it every day if you liked, providing it was limited to that laptop.
Activation would be another issue - generally you can only activate so often within a certain time-frame (I don't know what that time-frame is, but you'll be talking months I'd imagine), but you can ring them up and activate it over the phone.
I know recent Acer laptops can't be activated over the internet, but do work using the automated phone system (without having to be transferred to an operator). I'd be staggered if it isn't the same for all OEM laptops.
But it's all within the EULA. :)