Prossecor switch problems

[Beave]

i had a p4 1.8 processor laying around and my bro upgraded from his dell to a new computer

the mobo works fine with a 2.8 800mhz fsb and a 3.06 800mhz fsb

i put in the 1.8 but it doesnt post; i think it's the mobo no likeing a 400mhz fsb proc

http://www1.us.dell.com/content/products/productdetails.aspx/pedge_400sc?c=us&cs=&l=en&s=dfb&

thats the link to the computer

i have reset the cmos

any suggestions or help is appreciated

thanks

 

[earthscore]

(stating the obvious) are you sure they're the same socket?

 

[Beave]

(stating the obvious) are you sure they're the same socket?

yeah they are the same socket 478