Network card does not work after XP Pro Upgrade

I have being deploying windows xp to some 1000 computers across the hospital
and have encountered a problem where as sosme of the older models of pc's are
losing the drivers for their NIC's. To currenly resolve this we are manually
having to go to each problem pc and re-install the drivers, which is just not
convienient as we cover such a large site. The funny thing is, that the
drivers that are being used to re-install the NIC are the ones that were
current when the machines were 2k, so the same are able used after becoming
xp, so i do not know why they are not carrying over during the upgrade.
I have done a bit of reading up on the web and have come across some people
using devcon to resolve this issue. I have created two batch files (one
disable, the other enable). The thing is i do not really know how to put it
all together and with the upgrades.

Thanks in advance

Gemma