wtf?? what happend to my pc and how can i solve it?

[Drianos]

This is what happened: i turn on my pc today and it shows a screen with 2 accounts when i use to have only one that automatically log in.There was a guest account and another account that ask me for a username and a password, so i had to log in in the guest account and i cant do anything from that account, is like when you do a new account, no documents but it have all the programs installed before. I wanna use the system restore to get my pc roll back to yesterday to see if it works, but i cant since i need to run it as administror so the pop up appear asking you for permission and it says" to continue type administror passwod" but theres not even space to do that in the pop up, anyways i got no idia what that password can be.

there might be a possible cause, i found a program in a forum yesterday but in order to install i first had to run a program that change the sid of my pc, so i was like"wtf is that? i will just do it" and it says that dont restart your pc because it can cause OS problems or something like that,but it taked hours(and i mean hours) and there wasnt a progress bar so i thought maybe it was doing nothing so i close it, and continue with my day.

so i will appreciate if anyone can say me what happpen or if someone can tell me a solution, or maybe just tell me how to run system restore without admin rights.

in this moments i dont have any right at all, just a guest account, so i cant see alot of stuffs in my pc neither install or open programs that modify data