HP Pavilion a1605 upgrade and reloading

[RIMON]

I am having HP Pavilion a1605 vista of two years. I changed its AMD Athlon 64 3500 + with an AMD Athlon 64X2 48550th After having checked that it was consistent with its cm. I took the opportunity to move to 3 GB of RAM. Processor is now replaced, the memory is increased, but two things:
My Processor is not fully recognized in the BIOS or in Device Manager it is called AMD processor model unknown against by it in the bios is at 2400 mhz and 2 * 512 to 2500 mhz in cacheet manager.
When I ask the pc to restart it does not restart and ventilate continue turning. In fact it seems to block after leaving vista.

Can someone know solution for this ?

Thanks

[JamesMK]

I advise you to do clean re installation of Windows. It takes 30 minutes absolute maximum and you will know immediately if there are problems or not.

[Mateja]

The cm supports cpu, OK (socket AM2), but the bios version is correct? (The trouble is that I can find no information on the HP site about the bios /)

[LALETTE]

Removed DIMMs RAM you added and see if the problem persists.
No need to reinstall windows for a change of Processor.