[raaman]

What are the reasons and the causes for the server downtime? Can we do anything about it?

[skysnap]

Usually it's not the server but the application load which makes the server memory makes application slow. but in govt office standard answer is server is down lol. most of the time servers are not usually down.

[sweerie_banana]

The first thing you should do is check your network structure.
You can also reboot your server to see if there's a difference in how it's working. But before you begin anything you should back up your data. Did you do that?

[Fergal]

raaman if you can please reply a little more info you will get more helpful replies. You could start by telling us if this is a server you own and manage, or is it a server you are using which is owned by someone else, e.g. a web hosting company.