Help me plz cant boot

[rejunker]

hi i got one big problem i cant boot my pc if i klick on the start button the screen stays black so i gave my computer to some spezialists they told me that my mainboard is broken so i changed it and now i got one from msi but its still same problem i cant boot thats my pc

p4 ht extreme
geforce 9800 ultra
512 ddr ram
ah and by the way my monitor is working

 

[HoopaJoop]

If you hear the post, and the drives spinning up you may have a bad video card.

Actually from your specs it looks like you have a non-existant video card..

 

[rejunker]

well thats not the problem couse i got 2 of the newest video cards and i tryed them both so what could it be else?

 

[Lostfaith]

try your cpu in another working pc, maybe (or probably) it broke (probably burned) together with your motherboard.

btw if the videocard/memory is bad you'll hear beep codes.

 

[rejunker]

my cpu is ok i testet it + my main is ok 2

 

[shadow_29]

hey rejunker first of all which video card you have again.you wrote geforce 9800 ultra(well....you just wrote the combination of two different companies leading line up)either the geforce 6800 ultra(real expensive and power hungry but top of the line)or an ati radeon 9800 pro/non-pro(probably the most infamous card for gamers)if its the first one.then look no further because it draws a heck of a lot of power it has molex connector on it(the video card)check to see first if they are connected to a connector.you'll need atleast a 500w psu to handle the videocard,does yours match up?