Dimension E520 CPU Upgrade to E6600

G'day,

I'm upgrading a client's Dell E520  from a Pentium D 820 to a Pentium E6600 Dual-core CPU.

With the E6600 CPU installed, I get no POST screen at all, and the monitor light blinks. Both fans (PSU & CPU) come on and the hard drive spins up. The main front panel power light shows steady green and the front panel diagnostic lights show 1, 3 and 4.

To shut down I have to hold the power button in for 4-6 secs (rather than just pressing it).

All my research insists that the E6600 is compatible with the Dell E520, and it's my understanding that the motherboard should automatically adjust from the old 800MHz to the new 1066MHz FSB speed.

I'm using the original 305W PSU.

I have updated the BIOS from 1.x to 2.4.0.

I have tried reverting a RAM upgrade from 2x2Gb 800MHz (which works with the Pentium D CPU) to the original 2x512Mb 533MHz.

I've tried removing the battery for 15 minutes as well as shorting the CLRBIOS jumper.

I've tried reseating the CPU, the RAM and the power leads. Every time I insert the Pentium D it works, but I have yet to get anything out of the E6600.

I work at a static-free workstation and am using good quality thermal paste with the original heatsink assembly.

I've spent hours on this, and am definitely stuck - all help gratefully appreciated!

Thanks in advance and kind regards,

Matthew

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