Question : Getting "permission Denied" error when trying to access network computer

I am trying to network my desktop and laptop, and keep getting the error "\\computername is not accessible.You may not have permission to use this network resource.....

Both of the computers are running XP Pro.  The 2 computers use to be networked to one another, just using a CAT5 cable, and they worked fine.  Somewhere between getting a linksys router, changing to a satellite internet connection, and setting my Office up with a linksys router and network, these 2 home computers quit working.  I mention my office network because I bring my laptop in and connect to the office network via a different workgroup.  My laptop works wonderfully at work.

I have viewed the following link and tried many of the things listed here:
http://www.experts-exchange.com/Networking/Windows_Networking/Q_21303526.html?qid=21303526
Her problem ended up being norton, which I do not have loaded on either of my computers.  

More information:
-I have turned the firewalls COMPLETELY off on both computers.
-I do not currently have any  type of antivirus software on the computers.
-I have tried connecting the computers directly via a CAT5 cable (the way I had it before getting the satellite internet and router) and I now get a connection, but get the message "limited or no connectivity".
-DHCP is enabled on both computers, although I am not good with knowing if the IP addresses are assigned correctly.
-my desktop is set up as the main computer.  It connects to the internet fine.
-The router is the linksys wireless G, with the 4 access points along the back.  the laptop and desktop are connected to the access points via CAT5.
-when I go into the group policy security settings of the laptop, I get an error that "group policy settings could not be determined...the error returned when trying to retreive these settings from the local security policy database 'secedit.sdb'...The parameter is incorrect".  However, this computer works fine on the Office network, and the security settings are still displayed when I click OK.  I have also changed some settings in there (following instructions to try to solve this issue), and the settings were saved...even after reboot.

Please help me with this!  I have been searching the internet and trying things...and cannot figure it out.It very well may be something to do with the IP addresses, but I am not sure how they should be configured... DHCP should be taking care of that, right?

Answer : Getting "permission Denied" error when trying to access network computer

          *Make sure that you are using a cross-over cable for connecting both pcs
           *Since none of your computers is set as a DHCP server, you should manually configure ip addresses. For example assign one computer 192.168.1.2 ip and 255.255.255.0 subnetmask and assign 192.168.1.3 ip and 255.255.255.0 subnetmask to other computer.
           *Or if you want to set up a DHCP and let things work automatiaclly, right click the local network connection of one of your computers, click properties,click advance an enable internet connection sharing. This computer will act as a DHCP server and when you restart the other machine, it will retrieve an ip address.
           *To test connectivity between computers, try pinging.