A clean install is legal and has a lot of merit - so I'm not saying it's a great idea.
But before I would suggest you make
(1) a set of factory recovery DVDs (essentially copies of your factory recovery partition). It stinks a little if Lenovo don't allow this.
(2) With Macrium Reflect (free), Image all partitions on your HDD including the factory recovery partition.

(1) and (2) are just safeguards.