Apple mac wont connect to ethernet internet

hi i have just purchased two imac 27" with mac osx lion at work, and i havent had much experience with macs as i have always preferred windows or linux.

the problem i am having is that neither of the macs will connect via ethernet cable on the network where everyone connects with windows pcs fine.

i have tried to input a static ip address for the macs but it keeps coming up as ip address conflict (another device has the same address), i know that it isnt a conflict as i have set up all ip addresses for the network and scanned for ips before setting and know which ones are free.
i have also then tried to use dhcp on the wired side for the network and then tried dhcp for the macs, then i get the 169 (apipa address). very frustrating.

i then managed to get them connected to one (out of 4)wireless access point via dhcp but this also is very hit and miss, it will be one connected and the other not being able to or both not atall. we have 4 access points operating on a large site which it finds but wont connect to. (all other windows devices are fine)
static addresses wont work either as it comes up with ip address conflict.

they both work fine when i connect to a mobile phone using mobile hotspot etc.

i have also been onto my ISP and they dont have a clue, I have been onto apple they want to charge me to troubleshoot it.

i have also tried removing the locations and adding them and its still the same its doing my head in abit now as i think i have tried everything i can, i dont really want to get charged by apple for this as you think they should connect out of the box for the huge pricetage you think it would.

had anyone else had any problems with macs connecting to works networks etc or could anyone please help as i dont know much with macs.

i just dont understand why it works sometimes on wireless only on one specific access point and not atall on ethernet.

: other info on network

router - draytek ethernet router

access points onsite
- belkin (works on this one)
- 3 x edimax

all windows pcs used ethernet and wireless are fine
network printers are fine.

tried to plug machines into different ports connected to different switches etc, tried different cables.

sorry for the essay but can anyone please help it would be greatly appreciated. thanks

Source: http://forums.bit-tech.net/showthread.php?t=223875&goto=newpost

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