Maybe you have bad luck, a second bad AC Adaptor...
Mayby ou can try an after market adaptor with higher capacety.

Does anyone know if it is possible to power up the cooling fan?

Thanks for you info MaartenS! It seems that the BIOS is capable to support more modern CPU's I just upgraded with a T7500 (2,2 GHz) it runs fine! (BIOS 1.13) I think it is not neccesary to upgrade the PSU because the power consumption is about the same (35W) It is very easy to change the CPU, the ha...