somtimes

Hi, I am currently facing an Issue with my PC When It goes to Sleep it doesnt wake up somtimes (Basically hangs in sleep, numlock light doesnt change) and even after pressing the reset (or holding the shudown and then starting) the pc fans and stuff start running but the PC doesnt Boot I...

ok i am using windows xp sp2.... dont know about lan much....... when i go to view the computers on my lan... sometimes.. they just dont open up.... (i mean the files are not displayed an error sayng " the netwrok path is not assecible"////////// its a chance phenomenon ..... somtimes...