There could be tons of reasons. Firstly, has this happened before? And when you say sleep mode, you mean the monitor refuses to turn on? Or the OS you're running enters sleep mode.

I had some problems with my screen monitor awhile ago. How did I fix it? I got a laptop. :p

How's the video card? If it is not sending the appropriate H&V drive signals to the monitor, the monitor will go into sleep mode.

on boot up, hit F8, from the options select enable VGA mode.


problem solved

-Digital

well ppl ive had the more or less same problem and ive tried al lthe above
take out cmos battery ,jumpers clear bios blah blah blah. the fan comes on good howeva there is this red light labelled as led1 next to something called RI8 . i know the bestway to fix thisis toget something new.but no1 has ne ideas?

My system did not boot, when it gets to the place where it says Press ESC to go to the next page and DEL to enter set up. That's where it stops and my monitor starts blinking showing nothing.

My system did not boot, when it gets to the place where it says Press ESC to go to the next page and DEL to enter set up. That's where it stops and my monitor starts blinking showing nothing. Even though my keybaord is not picking let alone wanting to press F8. PLEASE HELP ME!!!!!!!!!!!!!

My computer monitor stays in sleep mode after installing video card

I have never seen a monitor with sleep mode feature ,sleep mode is a feature of Windows,so your computer is not booting into Windows for some reason is most likely whats happing ,could be that the video card is not compatible or is not working .

Maybe a lack of power? Is your PSU capable of powering your new card?

RE: the error with the bios; you should post that elsewhere as it's probably related to a hardware issue.