I have a late 2010 27" iMac (bought it late October) and downloaded Lion right after I received the unit. I come home from work today to go on and reply to some of my work related e-mails and realize when I hold down left shift and hit 'o', nothing happens. Shift works with every other key on my keyboard and 'o' works alone or even if I use the right shift. I contacted Apple and we tried a few things but nothing happened so the guy recommended I reinstall Lion. I'm aware of how to boot into the utility mode and reinstall from there but is this a fresh install (formats first)? My external is at work right now and I have a ton of music, pictures, work documents and such that I don't want to lose. So if I reinstall Lion on here, am I going to lose my data on the drive?