Hey guys hope you can help with my problem,

i currently have an Touchsmart IQ771uk, been running smoothly now for about 3 years until recently, all of a sudden the screen resolution will go really low and lines started to appear on the screen, initially i thought it was a driver problem and formatted my hard drive, initally this seemed to solve the problem for about a week, since then the problem seem to have worsened, i then changed the hard drive (thinking it was a hard drive fault) but this didt solve the problem, how the low resolution is pernament and windows doesnt load what so ever! It also displays asterix symbols during boot up myself and now it pauses  as the windows logo appears from start up then screen goes blank and the computer after awhile restarts with ablue screen confirming hardware fault and had to be restarted. tried formatting again however problem still persist!

thinking now its abit more serious, from what iv been reading on multiple forums loks like a GPU or motherboard fault, any ideas?

if itis a Motherboard fault living in the uk does anyone know where i can get a replacement?