Network troubleshooting

[thecubical]

Hey all,

I'm having some kind of problem with Redhat 8.0 on my network. Currently I have three computers with names and ips'

amy 192.168.0.3 (Windows 98SE)
daniel 192.168.0.1 (Windows Xp SP1)
linuxserver 192.168.0.5 (redhat 8.0)

daniel is setup to share internet with ics and all computers are on the subnet 255.255.255.0

I am almost sure that the network equipment works fine also as i have switched over cables numberous time and tested all port on the switch

For a while after booting up the linuxserver pc will communicate with all pcs fine then whenever i try to run something that uses network like yum or folding@home it works fine for a while then any downloading that is happening ceases to and the linuxserver pc can not communicate with the daniel pc however it will ping the amy pc quite happily with no errors. The daniel pc can also not ping the linuxserver pc. I also noticed the leds on the switch light up whilst pinging for both computers which also leads me to believe this is a software issue.

The network card is a D-Link 528TX which shouldnt matter though.

Could someone please suggest or help to to furhter investigate into this problem as I am a little new and am unshore what to check eg logs etc.

Thanks again
Everyone