"Windows can not access \\..."

Source

Try to connect as
\\pcname
\\ipaddress

net use \\computername gives error 234  -- same for \\ipaddress

net view \\computername gives error 53

But

net view shows all the computers

Solution

Enable Network Discovery. 

Click Start->Control Panel->Network and Sharing Center, click Change advanced sharing settings. Enable the option. 

If the issue persists, try to access another computer by entering \\computername in the Start Search box.

Solution

Connect to workgroup PCs via IP Address, i.e. \\xxx.xxx.xxx.xxx\sharename

The system is able to authenticate and connect.

Solution

Win7 under virtualization and using NAT? use BRIDGED and you can see all the computers

Solution 

Disable IPv6 in adapter properties.  This was a similar fix for XP\Vista networks when Vista was first released.

Solution

1. open network and sharing center
2. open change advanced sharing center
3. check under  home or network properties, if you have turned on network discovery and file and printer sharing
4. if off turn it on, save changes, exit center then check it again. if appears off again find on win7 help which services must be started for network discovery. (start those services)
Network discovery requires that the DNS Client, Function Discovery Resource Publication, SSDP Discovery, and UPnP Device Host services are started, that network discovery is allowed to communicate through Windows Firewall -->  from windows help
5. you can try also change adapter settings  on active adapter -> properties -> TCP/ IPv4 ->properties -> advanced -> wins -> use enable NetBIOS over TCP/IP

Easy Fix
Control Panel > System and Security> System "See Name of this computer" > Change Settings......... and there ya go. Change the name of your workgroup from "WORKGROUP" to what every you use.  The old XP default was MSHOME. Restart and your done.

Solution

.... When I kept trying things and tried to change workgroup names on the XP machines and told them I was on a business workgroup, each machine took my previous WG2 and changed it to WORKGROUP - so kind of for the __ of it I went around and changed all the workgroup names from WG2 to WORKGROUP and bingo - everyone now sees everybody else! 

Seems like Win7 wants everybody to belong to WORKGROUP and you're on your own if you want to call it anything else.

Solution 

START>Right Click on COMPUTER and select Properties.
Click on ADVANCED SYSTEM SETTINGS on the left.
Click on the COMPUTER NAME tab.
My Computer Description was blank. I added a computer description, clicked OK - then refreshed the Network folder and Wah-Lah! All of the workstations appeared.
Source

Solution I
The user you are authenticating as must have BOTH read rights to the share and read rights to the folder/files of that share. (Assuming you are sharing on an NTFS drive).
Go to the folder, and grant "Everyone" full control of the shared folder. (Later change this to "modify" if everything works)

(Grabbed image from google images; you should select "Everyone" ideally. If it's not in the list, hit "Add..." then type "Everyone". Once this works, you may want to consider limiting access to local users)
Solution II

Try the following, but please note you make changes to the registry at your own risk;

1. Go to your Start Menu and press ‘Run’. * If you do not have Run in your start menu you can find the Run program in your Programs folder, then select Accessoires and select Run from that list.
   
   
   1. Type in ‘regedit’ and press OK.
   2. Search for the following location:
      
      • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\
   3. Double click on 'everyoneincludesanonymous' and change the value data to 1.
      Image
   4. Double click on ‘NoLmHash’ and change the value data to 0.
      Image
   5. Search for the following location:
      
      
      • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanServer\Parameters\
   6. Double click on ‘restrictnullsessaccess’ and change the value data to 0.
      Image
   7. Close the register editor.
   8. Restart your PC.