I am having problems initially booting up my computer. I first press the start button and the computer comes on however no beep and no boot-up. After pressing the reset button several times, it catches and there's a beep and the computer boots up. Once on, the computer works marvelously. It also shuts down perfectly.

Other times, I press the start button, switch the computer off with the switch on the power supply, put it back on and depress the start button again. I'll do this a couple of times and the computer finally beeps and boots up.

I have replaced the power supply believing it to be the main problem.

I have an Asus A7V Mobo with 800 mhz AMD Duron, 256 meg Crucial SDRam 168 pin PC 133 CL2, 64meg ATI Radeon 7000 Graphic card, Creative Sound Blaster Live Value Sound card, 40 GB Western Digital HDD

Not sure if this is coincidence but I have noticed that after I have used the computer for some time and shut it down - I wait a few minutes and restart the computer and it boots up normally.

Does your Clock keep good time?

Might I suggest replacing the cmos battery.
and check for corrosion around the battery...

It might be getting a surface charge while running for a period of time...
Which would account for it working after being powered up for awhile...

It is something that is quick and easy to try...

I have just replaced the cmos battery and there was no corrosion around the old battery. However, the same problem exists. Could it be with the motherboard, i.e capacitors?

Is the PC temperature sensitive?

Does it boot easier if the room is warm?

With a new power supply and a new CMOS battery I am beginning to suspect a cracked trace on the MB.

Did this start after swapping cards?

How many cards are in the system?

Have you tried it with only the video card in the system?

Have you tried a different video card?

Can you change the cmos to be always on and no power management so that it only turns on by the switch on the power supply (or power strip)

i've had this problem, or rather my bro's pc did you'll find you have to replace the mobo, i expect, so you may aswell do that, instead of buying new stuff to go on it to see if that fixes it

GLHF