Computer light flashes but monitor doesn't display anything

[cheeseMonster]

Hi peeps, I tried searching for any similar questions/resolved posts but couldn't find anything.

I've had an iQon cpu and Philips monitor for 4 years running on Windows XP. A few months ago I turned it on but the light kept flashing on the cpu while the monitor displayed nothing. This continually happened everytime I turned it on, then one day it worked and I was able to use the computer for one day. Then as soon as I switched it off and tried to use it again, the same problems began.

I've tried using a different monitor and plugging the cpu in a different socket, but to no avail. When I switch the monitor on, the light on the switch of the monitor keeps blinking, as if to say the cpu is turned off/isn't relaying any information to it.

The fan on the cpu still works, so I dunno, I'm just wondering if there's any suggestions, bearing in mind I'm a novice when it comes to hardware! Thanks.

(meh, just realised this is posted in software, not hardware, apologies) 

[Mikehg]

may be the picture tube is not functioning..