Hardware or Software Problem?????

Ok i been having lots of problems with my compute lately,
it has just started recently. At first my computer would
just lock up , simple restart would fix it every time, it
usually didnt occur very often. But then it got more
frequent, then i had more problems, my computer had
problems starting up, it would freeze during various
stages of booting up, if i made it to windows i was fine
unless it locked up while i was using it. It wasnt as bad
i just reset it and it would go correctly again, but it
got progressively worse, to the point where my video card
isnt even regeistering anymore, i turn on my computer and
alls i have is a black screen and i think my har drive is
trying to spin but its not working, i could get on my
computer by ids have to reset it till it finally wen
through and i got into windows, i then ran virus scan,
and it came up clean, prblem persistested so i
reformatted. That seemed to do the trick worked fine for
a few days and then dejavu all over, did the exect same
thing this time, to the point i cant even get it on
anymore? can anyone please help me with this, i built he
computer a year ago and this just started past month or
so, and help is greattly appreciate, thanx in advance