my network does slow down after every 5 minutes (more or less) of net activity. after several minutes, it goes back normally. the OS before was windows 2000 advanced server and i've tried installing the windows XP as a server in another computer (server capable). for about 5 (i think) hours after i've installed the XP. the network was working pretty good including the net activity of workstations. there is no problem in LAN actually. it seems like just our internet connection goes slow. so i've uninstalled the XP (formatted, unpartitioned) and installed linux (gutsy gibbon). now, my server is fine and working good for several days. just before the year ends. the problem occured once again.

does anyone had the same problem with their network or maybe i was infiltrated with virus or spam or whatever?

i badly need some help. thank you.