DNS ISSUES

Is there any error?

Can you let us know a bit about your DNS setup?  
Do your workstations have a secondary DNS configured?  (if so, what does it point at)
Does your DNS server use your ISP's DNS server's as forwarders?

When the issue next occurs:  try to ping a problematic device by name.  What address is this name resolving to WHEN the problem occurs?  Does this IP address exist ANYWHERE in your DNS server?  Or, if the name FAILS to resolve, even though it usually works, this would indicate some kind of problem with your DNS server or it's connection.

Don't use DNS because it adds complexity which appears to be the issue.
Use static IP addresses for the printers and address them accordingly on the client machines.
Subject to how you have things set up but this is most typical.

Frmarshall - In a domain environment, you need DNS to work.

One more thing - please ensure your windows updates are all installed.

The errors are Outlook cannot connect to exchange, sharepoint - page not displayed and for printers user prints but nothing happens.

When we ping the dns server from a machine that is having the issue, we get a response to both name and IP, the DNS server name is an entry on the dns server as well as the client machine. However the next time it happens, I will double check those points.

DNS is a requirement here, especially for Domain and Exchange connectivity.  You need to authenticate to DCs, etc, so you HAVE to have DNS.

Where is DNS on your network?  Is it running on a DC?  If so, can you check the logs to see if there are any errors or warnings?

In a domain environment, IP addresses still work.  Why use DNS when you don't have to?  Just because it's there isn't a good enough reason.  Yes, some will claim that it makes their lives easier.  But that's dependent on the size of the network, how many people are involved in messing with it, etc. etc.

FMarshall - DNS resolves the internal hostnames to IPs like WINS used to do a couple of years ago, however, WINS is much slower and DNS has it's own resilience hence Microsoft made it a necessity since Windows Server 2000.

@fmarshall - you need DNS in a domain environment for a whole load of reasons.  Active Directory won't even install on a server without DNS being present.

Exchange relies on DNS.  It's mandatory in a domain environment even if Exchange is installed on a Domain Controller.

Clients NEED DNS in order to authenticate to a Domain Controller.  Without DNS a client wouldn't be able to locate SRV records, etc.

Sure, IP addresses still work for static devices such as printers, but I think you miss the point here.  The fact is that DNS is failing somewhere and in an AD environment that's catastrophic.  So, instead of bypassing the issue by using IP addresses we have to fix the DNS problem.  In any case, if the printer is shared from a server or client PC on the network users won't be able to authenticate to the host to actually print unless the print-server is a DC.  That's even more reason to fix the DNS issue.

craigbeck and Imtiaz:  I had narrowed the question down to just printers and now see that it's broader than that.  I stick with what I said about network (IP addressed) printers.  You don't need DNS for them to work.  How you implement them is a matter of preference.  But you may well need DNS to work for other things like Outlook, shared printers, printers on a server, etc.

If the printer is standalone (not shared from a PC or server) using an IP to reference it is fine, but if AD security permissions govern printer access DNS is required.

I agree to preference of using IP addresses for printers, however, the issue here is Outlook and sharepoint losing connectivity - Hence my concern.

We agree it appears.  Y'all know better than I about those things.
Why would one want to have AD security permissions governing printers?  To save paper?

Oh fmarshall...

Some documents are sensitive. We control how they are distributed and reproduced using security permissions on drives, printers, etc...

We use permissions on shared printers to determine who can print to departmental printers (to manage printing costs, etc) and to ensure only authorised people can manage the printer or print queue.

There are lots of reasons why permissions are used.