why my pc doesnt want to boot on normal mode?

[arix]

My pc was running pretty nice and smooth.... but a few days ago i unplugged it to move it to another room... well this is the problem: when i start my machine it doesnt boot directly to windows... it says something like boot error o something simillar... but when i go to the bios and select "LOAD FAIL SAFE DEFAULTS" it boots but it takes a long time to display the win xp loading screen, then it loads normally... I just want to set it up like i had it before, what should i do??
my cousin told me that i have to con to my pc>properties>Advanced>and click the 3rd option... then he told me what to do but i dont remember....

[Cricket]

Since you moved the computer, did you open the case up to see if anything came loose?

:) Cricket