What I should have done is to clean-install the system right after I bought it.
Fortunately, you didn't.
First issue is that you would lose your Windows license: the image installed on your laptop is tied to both the vendor and your mobo (more specifically, your MAC address), so you would have to purchase another copy of Windows just to do a clean install...and kiss the other license goodbye. As an experiment, take a Dell computer and install a retail copy of the same version of Windows...when prompted for the product key, enter the key stamped into the sticker on the side of the case....you'll then notice the Windows installer specifies that the key is invalid.
Second issue is that many laptops have proprietary devices that require proprietary drivers. For example, notice how OEMs charge you for an XP downgrade disc if you don't like Vista (or Win7)? That's because they need to write drivers, test them, and create restore discs (they don't just send you an OEM copy of Windows). If you used a standard retail disc to install Windows, you're on your own for finding drivers...many drivers for specific devices do not have drivers available for download, since the OEM has had no need to release updated drivers, therefore you're already (supposedly) using the L&G and there is no need to make the drivers available.
And once you have mucked up your machine enough, you can drop in the restore disc the OEM supplied you with, and revert the machine back to Day One condition in about 15 minutes.
No, what you should have done was to install Decrapifier right after you bought it.