Checkpoint SecureClient failing to authenticate (gateway not responding)

Right click the Check Point yellow key icon in the Task Tray (lower right by the time), choose Tools > Disable Security Policy

Now try and connect.  If you are using SecureClient, the default Desktop security policy could be causing this.

These aren't Dell laptops are they?  Dell has a Checkpoint SSL VPN client included in their network connectivity management application that caused many problems with the full checkpoint vpn client (SecuRemote and SecureClient).  Couldn't get the CheckPoint client working until I uninstalled Dell's utility, then installed SecureClient.

Thanks for the ideas.  "Disable Security Policy" is grayed out so I presume it's set by the client on the far end.  Also, my working PCs must therefore be the same security policy.  This works when I have no firewall in between.  But I don't see the server packets going to the firewall - in fact I dropped a packet sniffer on a hub between the failing client and the LAN and the server packets never showed up on the sniffer - so I can only assume that the client is consuming them somehow - why, I have no idea.

Did you configure the desktop security policy in the Check Point firewall?  
Desktop Security policies can be defined by login, client, and/or VPN client certificate.

Are you sure the options are set the same?  There are options in the client for traversing NAT.

Did you use the same installer file on the 3 new PCs that you used to on the working PCs?    

The SecureClient has a packaging tool that allows you to customize the installer, set defaults and options and lock them as well.  Are you using the unpackaged client?

Did you try temporarily disabling  XP or Security Suite firewall to see if that helps?

As cybervzhn says, di disable other firewall products on the afflicted machine as these can sometimes affect the VPN. Do you have any other vpn clients installed on this machine? If so, try uninstalling those - vpn clients are notorious for inexplicable problems if multiple clients are installed on one machine.

The desktop security will be greyed out until the desktop policy has been configured on the policy server it is connecting to i.e. the main site which happens when it connects in for the first time.

Also, have you installed SecureClient or SecureRemote? You will be able to tell by doing an ipconfig/all:

If you see something with a description of:

Description . . . . . . . . . . . : Check Point Virtual Network Adapter For SecureClient - SecuRemote Miniport

then you have secureclient installed. Please check this against the other 2 working clients.

Thanks for the ideas - here is the situation. First, I have no control over the checkpoint equipment.  It belongs to a customer and we were just given a procedure for installing/site creation/connection etc.  We are using SecureClient.  Standard downloaded install from CP.  No software firewalls.  All the PC's are domain members with the same group policies applied so working/non-working machines should be identical for security purposes.
More information:  On Friday I had two working PCs that had been installed/configured a year ago.  This morning on a hunch I deleted the site from a working one and re-added it.  It behaved like all the other new installs - it adds the site, and then fails in the same manner - packet traces are the same as my other failed attempts.  So - what is working is the older "SITE", not the older install.  I don't know anything about checkpoint equipment but this suggests to me that some policies created by the admin on the far end are interfering with  this once they are pushed out to the client.  Does this make sense as an approach?  If so, I will push this problem back to the customer's IT (although in the meantime we cannot be productive so I still need to think about a workaround).  Thanks so much.