Losing network on PS3

[#1]

I was just wondering if anyone can given me a nextstep on what to do,
I seem to lose network between my PS3 and router i have had it running before without any problems.
My internet is still running and network to PC seems to work fine.
~I have tried changing network cables (cat5)
~used a diffrent router belkin N+ and a sweex adsl+2 both with same problem.
~resetting both routers to default
~turning all firewalls off and putting DMZ on
~updated both routers too newest firmware/patch
~manualy putting  details onto playstation
This started happening about 4 days ago sometimes it only cuts out within a few seconds and then sometimes it can last for hours.
The playstation doesnt seem to be over heating or making noises. and with all ports open i have no clue where to turn.
also my internet does cut out once and awhile. this happens with all games i play. Modern warfare 2 , everybodys golf world tour , rock band 2 and others
I would be very greatful of any help.

[#2]

When the network is lost, can you still access the router config page on the PS3 browser?  Do you have connectivity on other things (PC?)

[#3]

I can gain normal access on my PC, Havent found anything that doesnt work.
Also i cant gain access to my router config on my PS3, The network lights on router and P33 stop showing.

[#4]

Have you tried connecting them wirelessly?

[#5]

I have tried my belkin to PS3 but shows nothing when scaning. my mobile phone finds about 6 diffrent wireless networks but my PS3 cant seem to find any of them.