what could be causing this start-up problem.
SOMETIMES when i press the start button, the tower seems to be running, but there are no beeps and the screen does not light up.
if i switch off at the wall socket, then switch on again at the socket, , then press the start button, win xp starts up o.k !!
this intermittent fault is annoying.
ayone give me POSSIBLE causes
thanks
(i have an athlon 2200 xp processor and 512 memory)
tonyVerify the power supply units functionality by testing it on another computer.

Reset BIOS.ah! how do i reset the bios??

but there seems to be power in the pc, but the thing doesnt boot up(not just windows, but the "dos " screen eitherah! how do i reset the bios??

but there seems to be power in the pc, but the thing doesnt boot up(not just windows, but the "dos " screen eitherhow to reset the bios??How to enter the BIOS/CMOS setup

or

To reset the BIOS, take the following steps:

1. Power down computer
2. Take measures against electro-static discharge
3. Remove computer casing
4. Inspect mainboard for a CMOS jump switch or CMOS battery (Most systems have either)

In CASE of CMOS jump switch being present :

Follow instructions provided with the mainboard manual.

In case of CMOS battery present :

I. Remove CMOS battery for approximately 10-15 seconds.
II. After 10-15 seconds, place the CMOS battery back.

5. Power on system.

Do not power on the system when the CMOS jumper is set to clear_cmos or when  the CMOS battery is not present. here is another symptom that i have noticed.
the firsr "beep", that switches on the screen occurs at different lenghts of time, sometimes 2-3 secs, sometimes 10-15 secs, is that a clue to some thing??
thanks
tonySee this article. ::)thanks for all the info.

looks like i have a lot of things to check out !!You need to know:

• Beep code
  
• BIOS name
  

it says amibios at the initial boot screen, and when it doesnt light up the screen, there are no beeps at all.
usually one beep lights the screen, and then another one just before win xp starts.
if the onboard graphics was a bit dodgy would that cause my problems ?

sometimes 2-3 secs, sometimes 10-15 secs

there are no beeps at all.