I am experiencing some problems with the network at my office.I notice that systems disconnects and reconnects randomly.This happens to systems even on the same switch where one disconnects,the other does not.I have tried changing the switches to new ones but the problem still persists.Would be glad if someone can give me some suggestions on what to do.Could it be that a worm has infected the network?

Be sure that your network has not been infected with a virus.
Run your updated antivirus. If no virus is detected, then make sure
that there is no ip address conflict.

ping the network card to be sure that they are functional and are not failing.
click start-> Run -> type cmd,
then press Enter key.
Command prompt comes up.

try typing in the command prompt the command below:
ping localhost -t

if there are no replies or erratic replies, then consider changing ur network card.

This issue has to be treated with some technical skills and experiences. Observe that only one problem can be caused by many things in computer system. Since you said the systems use to disconnect and reconnect randomly, I will say you should observe how it happen and when exactly do is happen.

Another thing is when did it start, what have you notice before it started?

But I didn't know the type of network and OPS you're using, therefore my advice for you is to reconfigure the network setting of your company network or You can tell me the Type of network and the operating system used. You may send it to adeniyi12002@yahoo.com or call/text 08067999673 for more information