Dell GX520 SFF CPU UPGRADED BUT BOOT ERROR MESSAGE

[Dudz]

Hi I have a Dell Optiplex GX520 sff...My cpu was a 2.6GHZ..
..I have now upgraded to a Intel Pentium P4 661 Processor 3.60GHz 800FSB cpu / Part Number HH80552PG1042M / cpu Speed 3.6GHz / Package Type LGA775 L2 Cache 2 MB

I updated the system bios from the Dell support website
My pc works fine with it,except on start-up it states ¨incompatible cpu found¨ then askes to use F1 to start windows normaly or F2 keys to run system setup........but after pressing F1 it starts into windows and works fine and even shows the correct cpu values
I have tryed reseting the NVram (as advised) , but this seems to make no difference. Any suggestions ?

I have contacted Dell support for answers but they refuse to get involved with CPU upgrade issues.

[Guest]

Does nobody know ??

[Marcin]

I had same experience with Acer PC. There was able to download and update CPU code into BIOS from DOS boot disk. Was useful but only for max PIII 800 - I mounted Celeron Tualatin 1200 so my problem wasn't fixed.