First time builder needs help

so i spent my whole evening putting this build together and when i first power it up it acts as though it will boot but then turn off, then try to boot again and over and over, once in a blue moon it'll actually get to the bios. looking inside i notice the cpu fan doesnt start up right away but eventually starts if the pc actually gets to the bios screen.

build specs are as follows:

Antec Sonata III 500 with built in 500w power supply with 80% efficiency

GIGABYTE GA-EP45-UD3P LGA 775 ATX motherboard

Intel core 2 quad 8200

Asus Radeon 4850

Western Digital 640 gb harddrive

Samsung 22x dvd burner black SATA model

Corsair 4gb RAM

Thanks for any help and suggestions

so i spent my whole evening putting this build together and when i first power it up it acts as though it will boot but then turn off, then try to boot again and over and over, once in a blue moon it'll actually get to the bios. looking inside i notice the cpu fan doesnt start up right away but eventually starts if the pc actually gets to the bios screen.

build specs are as follows:

Antec Sonata III 500 with built in 500w power supply with 80% efficiency

GIGABYTE GA-EP45-UD3P LGA 775 ATX motherboard

Intel core 2 quad 8200

Asus Radeon 4850

Western Digital 640 gb harddrive

Samsung 22x dvd burner black SATA model

Corsair 4gb RAM

Thanks for any help and suggestions

Sackettmyer

Here are some suggestions:

CPU overheat.   heat sink maybe installed incorrectly.

Memory.  You may have faulty mem stick(s). OR, If you did  not buy all the memory(supposing that its not just a 4gb stick) as a kit, check th CAS latency. Sometimes even the same type of memory can have different latency's

Power. Check your motherboard manual for minumin PSU requirements. Some manuals have charts that include components on power requirements. OR, PSU is faulty. check all conections[ 12v, main power, video card if appicable]

I had a similar problem with an asus striker extreme board. It ended up being a voltage setting in BIOS. Since I could not access Bios, I ended up RMA'in the Board.

Good luck to ya.