Hi, a while ago i built my pc, it has been great but now it won't start. At first it started to freeze within windows, which was annoying. then it started to freeze within startup, which was worse. but now it won't start at all. i turn the switch on, the processor fan goes, the hard drive spins, makes a "thinking" noise, but there is no beep and startup. i could leave it for hours and it wouldn't do anything. it was suggested that it was the graphics card as it wasn't "posting". so i took it out, put it back and then it worked, but then stopped working. i then got another graphics, which i knew worked but i have come to no avail. Any ideas? its been 3 weeks now.