Re sanding pine floorboards.

[colsnr]

My bedroom is empty at the moment as its about to have the walls skimmed. it seems an ideal opportunity to refresh the already sanded and sealed pine floorboards. they were sanded and sealed about 8 yrs ago so look a bit tired compared to the other rooms ive done recently with hired machines.

I have a 150mm dewalt random orbital sander, could I use this to clear off the seal thats on them and if so what grits of sandpaper should I be using?

Do I need to get right back to the wood? or just key the surface and reseal?

Thanks