help me a bit

hey everyone my name is xplode16
i haven't been on in about a couple months so i am probably not known
introductions are done
the other day i was just going around surfing the web and then the comp shuts down
i start it back up and the only account is now a guest account not a admin and a new thing says other account.
a bunch of my files have been erased so im just wondering if any of you could help me cause this is really annoying
i cant access any of the system things like system restore or anything cause it says "please enter the pass for admin" bla bla bla i dont have one and it doesnt let you
and im running on shitty windows vista sp1 basic 64 bit

u coud do a system restore doing it by restarting ur computer and pressing f10 and do a manual reboot u dont need admin for that

let me know if it helps u out

Open command.exe,
Type Net Localgroup administrator <thenamehere> /ADD

Tell me if worked, if not, tell me what error it gave

Erm maybe u have to format?