thanks wolfemole, i sorted it, i tried fast formatting first, but that didnt work so later tried slow formatting (someone advised me that slow formatting is better) eventually after sorting above problem, pc would only boot in safe mode, i fixed this but dont really know how! i tried chkdsk /p, /r , i tried fix mbr, tried fix boot, opened cover and removed different components (ram, dvd etc) to see if was a hardware problem. looked in msconfig at boot ini to see if start in safe mode ticked (it wasnt). downloaded new display driver etc. it just booted up!!! dont know what i done!!