computer won't start!

hello! i am new to google groups and i hope that someone can help me
out here. i recently purchased a new processor from Newegg. It's the
amd 64 x2 4400 toledo. i was hoping that i could just replace it with
my older processor, an amd 64 3200 venice (which is currently oc'd
from 2.0ghz to 2.3ghz). After replacing the processor, the computer
would power on for a split second and then die. i reset the cmos and
tried it again but to no avail. I thought i blew something out so i
put the old proc back in and here i am now typing up this issue. the
specs of my computer are
MSI K8N nForce4 mobo
2x 512mb corsair ram
geforce 6600 GT
Phoenix - AwardBIOS v6.00PG
Orion 420W PSU
2 harddrives
Could it be that the processor is DOA? Any help is appreciated!