Network Choaking Issue

Hi Team,

Kindly Suggest me what should i follow the Guidelines when LAN Choaks as we are not having proper monitor Tools & Friendly Troublehooting softwares

We are using  Ethereal & Wireshark  softwares but it is not helping us in a Friendly manner and the statistics is not good.If you suggest the above softwares try to provide how  can i use in a Proper manner to get the issue to be resolved


Our Network scenario is

a) All Project rooms are centrally connected to the one Core switch 4510 series with  fiber
uplinks
b) No VLANs , all are in default-VLAN

c) No access-lists /  DHCP server configuration / No secured configuration ,it is default plane configuration

1) How to find out which system causes the Network Choak and also suggest a good Monitoring Software which can easily identifies the PC/server .

2) Through any Cisco Switch command can i find the Network Choak.

3) What is you recommondded configuration do i need at Central switch to overcome the issue

4) Suggest any scenario modification so that we will plan to change accordingly

5) Suggest good software which will show the Network perfomence and Deffected systems

It is high importance request from me.Pls help on this regard with a Helpful commments and also let me know if you want any other info from me

Regards
Ram