internet connection 'sleeping'?

I have 3 computers on a home network / workgroup. All run XP Home SP2 with
all the updates. Netgear wireless router MR814v2 on computer 1. Computer 2
has Netgear USB adapter, computer 3 (laptop) has D-Link wireless card.
Machine 2 and 3 work fine. They access each others shared files and internet
without issue. While they both could always 'see' computer 1 on the
network....they were never able to access it. There are shared folders on
1...firewall is set to off. I always get the message that I'm not able to
access it...may not have permission...contact network administrator. 1 has
always been able to access files on 2 and 3.
Internet connection on 1 always worked well every time....fast and available.
Because 2 and 3 could not access it...I ran the 'setup wizard' on 1 thinking
it would fix the problem. It ran without issue and said everything was
complete.
Now.....2 and 3 still work great in every way between themselves. They can
still 'see' 1 in the workgroup but not access it (so everything is the same
as before).
1 (main computer) can still work with 2 and 3...but now the internet
connection seems to go to sleep. Every time I try to access...I get a pop up
saying there is no connection to the internet and I have the option to 'work
offline' or 'try again'. When I click 'try again' everything is perfectly
fine.
Somehow...the 'wizard' did not fix the network problem....but has fouled up
how my internet connection is 'sensed' or determined.
Any ideas would be greatly appreciated. After all this, it would be great to
have an actual network.....but now all I want is to have reliable internet.