Help!!!! Everything is gone!!!!?

My 2006 HP Home Computer crashed last night. I logged on as usual and then it shut off and started to restart by going to Windows XP start page, then HP Invent then a black page with options like "last known good configuration" and the F5 didn't work. Then back to start windows. it did this cycle for hours, even after we unplugged and restarted it twice. Then someone went to the PC Recovery or Restart page and we had to answer all these Q's like it was brand new computer. Then when i went on to my account, the little user picture that i had used before was still on there but my account was gone!! MY bookmarks, mcripts, WMP music, pictures are all gone, but that one picture in there was still on. Is there anyone to go back to my old account or get my stuff back??? Please help me!!