Why are packets lost in a peer-to-peer network?

Question

Computer networks

Good day!
There is a peer-to-peer network from 15 PCs.
13 PCs in one group, 2 are connected via lan at a certain time (laptops)
The network consists of a gateway (ZyXEL P660HN Lite EE) - an old model
of 4 stupid switches.
Network speed - 100 MB.
The router itself distributes ip addresses.
of these 15 PCs, there is one PC running WinXP (a file dump where people drop their files and exchange)
The essence of the problem: when transferring or working in a file that lies exclusively on the file dump, they start to freeze. Word/Excel documents, etc.
I pinged this file dump from all PCs, the ping is lost randomly, for example, out of 2000 packets, 3-4 pieces are lost, or maybe 40 pieces.
What I did: I changed the twisted-pair cable from the file cleaner to the PC (compressed with a direct standard B), I changed the switch from which the connection to the PC goes.
I inserted built-in network cards on the PC and the file cleaner (I sinned on them).
All the same, when pinging, packets are lost, it writes "the waiting interval for the request has been exceeded" literally 3-4 packets are lost and the ping goes on again. The file cleaner is registered ip and mask in TCP/IP. It does not go to the Internet and there is no DNS (for there is no need)
Tell me how to set up the network or diagnose, I can not solve this problem.
The other day I turned on only 3 PCs - File Cleaning and 2 any PCs, the network was stable for 3-4 hours. Everything worked as it should, but as soon as the working day came, people started working immediately, packets began to be lost ....

Answer 1

The symptom "n works for 5 seconds, does not work for 5 seconds" is an overload of the packet queue on one of the switches (do you definitely have switches and not hubs?) on the way to the trash: when overflowing, packets start to be discarded.

Answer 2

Change router to Mikrotik. at least 951 with gigabit ports. And I would put gigabit switches.
But the router first. And stick a file cleaner into it.
I would also like to change XP, well, at least for 2003.
Then get users, so that everyone goes to file storage under their own account, and not under one guest account everyone breaks

Answer 3

Packets are lost under heavy load. If everything changed, then the problem is in Windows, a network card or a card driver in a file cleaner.
Put the ADSL modem in bridge mode, followed by a normal router with gigabit ports and a switch also with gigabit ports. The file washer can temporarily roll another Windows or take another computer, perhaps there is a problem in Windows. Gigabit network cards are everywhere, re-compress the cables with a good crimp or buy factory patch cords.

Answer 4

Switch overload. If these are cheap stupid unmanaged switches - no wonder. Change to something more professional like the old ones from cisco - they can be found for 1500-2000 rubles. for 24 ports on sales, for an office of 4 switches this is a penny.

Answer 5

update the network card drivers, the capacitors may have dried up