my screen froze momentarily, the image went sort of jagged, then the monitor went to sleep. I switched the monior back on and it went though the start up routine scanning for signals but said it could find none and went to sleep again. I tried it again later and everything worked OK for a while then it happened again and got more frequent but was still usable now and then but now I can't get anything at all from the monitor. The desktop sounds OK and the monitor comes on scans for signals but goes to sleep. I have tried a different cable but no good. I haven't tried a different monitor as it seems to be working. I opened the box up as I thought I could try another graphics card but it integral. It is a HP desktop, running Windows 7. I can't get anymore info as I obviously can not use a monitor.