New PSU seems to not power SATA/ IDE (OCZ550FTY)

Hi,
I needed to replace my power supply in my 4 year old custom PC which worked fine until recently, now I bought a PSU OCZ550FTY to replace it.

My system spec:

AMD Athlon Dualcore 2200
Motherboard: M2N32-SLI Deluxe
Graphic Card -works fine, it's a Club 3D M2N32-SLI
2GB memory

Peripherals: I got 1 SATA hard drive, 1 SATA DVD drive, 1 old IDE hard drive.

Now when I installed the PSU, the system wouldn't want to boot up and I tracked it down to the peripherals connectors- when I unplugged all peripherals, it did boot.
I tried around a little bit with different combinations and it's now booting with all peripherals connected - but it won't recognize any of the drives in the Bios. I also can't open the DVD tray so there is a definite indicator that the drives are not powered for whatever reason.
There is definitely power on the 5V rails though - as the chassi fans are connected to that as well and they start up


The hardware monitor in the bios says it only delivers 4.86V on the 5V channel - not sure if this difference can cause these problems..

what can be the problem? Is the power supply not compatible with my 4 year old system?