Computer Meltdown!

Ugh!!  I was having some really annoying problems with my Mac recently, mostly related to iTunes and my iPhone.  I took both my Mac desktop (which is HUGE) and my iPhone to the Genius Bar yesterday and it took about 2 hours for them to (hopefully) get it fixed.  They were afraid they were going to have to wipe the Mac totally clean and start over if they couldn't get it fixed...ugh!!!  So, he created a new user for me and now I have NO IDEA where all my stuff is and how to find it!!  I am so confused!!  The Genius was stumped for awhile and said he has NEVER seen this problem before, but at the same time, he was excited to have something new and different to challenge him.  He was a self admitted GEEK! (his words not mine!!).  But whatever he wants to call himself, to me he will always be a GENIUS for getting my computer working again...now I just have to figure out how to find everything...wish me luck!!