Home network not working

Ok, I have 5 PC's networked, all of them can access the internet thourgh the same DSL router.
1. Main Xp SP2
2. Laptop XP SP2
3. Wife's XP SP2
4. 400 98 2nd ed
5 128 98 2nd ed

I use to be able to transfer files from anyone of them to any other one. Now The 2 with windows 98 only see each other and my wife's. My laptop doesn't see another PC on the network. And the Main one didn't see the any for a long time, then when I upgraded to SP2 it saw all of them and now has stopped seeing all but the 400, but when I try to access the 400 over the network I get a msg saying I don't have permissions.

Would making an XP network disk and running it on all of the machines be the best place to start to try to fix this? Or are there other suggestions I should look at first?

 

Ther is a big probability thta it will make it worse.

Log to this page it has a lot of links to instructions to Windows Network Settings, and Sharing.

Link to: Windows Network - Sharing.

 

DISABLE sp2 firewall...

or put file and print sharing in the "exception"

it'll work after....

*&^%^%$ m$firewall