I have a olympus VN 5500PC. after connecting to the computer it showes that there are no files in it, but i can hear the recorded files right from the device while it's not connected to the comput

SOURCE: olympus vn-2100pc

check out this link, i had exactly the same problem but this blogger has a working patch for the vn-2100pc and vista - works fine now!!

http://blog.ironguard.net/2007/06/olympus-vn-2100pc-and-windows-vista.html

SOURCE: Can't seem to transfer files to computer

The memory is probably corrupt. Use the reformat feature from the menu. Any recordings will be lost.

SOURCE: How do I transfer files to computer from Olympus VN-3100PC?

There are many steps in installing Digital Wave Player on VISTA, it is important to follow every step since installing Digital Wave Player on VISTA is dependent on this process.
Install a VN recorder on VISTA
*************************
1. Make sure the device has been uninstalled in device manager
2. Make sure the old version of digital wave player is uninstalled.
{Delete Temp files in Internet Explorer --Tools--Internet Options --Delete Files-- Delete offline content--OK}
3. Install digital wave player (The newest Version).
http://www.olympusamerica.com/files/DigitalWavePlayer.zip
4. Install the 2.1.4 vista update
http://olympusamerica.com/cpg_section/software_results.asp?id=1291&os=w
5. Restart the computer.
6. Plug in the VN recorder to the USB port and turn the recorder on.
"Found new hardware" will appear,
7. install automatically.
This may fail, if you see VNUSB device, skip the final steps and proceed to Digital Wave Player to Download files from the Digital Voice Recorder.
If you will see "Other devices" listed in Device manager with "digital voice recorder" underneath it.
8. Right click on the "digital voice recorder"
9. Select update driver from the pop up menu.
10. Choose the browse computer Option
11. Browse to the location on your computer where you downloaded and saved the Digital Wave Player files from Step 3
12. Click Next
A security warning window will open,
13. Choose "install anyway" and the device will install.
When successfully installed you will see the "other devices" disappear and a VNUSB device with a "VN series device"
underneath it appear at the bottom of the device manager list. There will be a blue question mark next to the device. At this point you can close the device manager and the properties window and open Digital Wave Player. You will see the recorder listed underneath the recorder folder and be able to download and use the program normally now.

SOURCE: Digital voice recorder connection problem

There are many steps in installing Digital Wave Player on VISTA, it is important to follow every step since installing Digital Wave Player on VISTA is dependent on this process.
Install a VN recorder on VISTA
*************************
1. Make sure the device has been uninstalled in device manager
2. Make sure the old version of digital wave player is uninstalled.
{Delete Temp files in Internet Explorer --Tools--Internet Options --Delete Files-- Delete offline content--OK}
3. Install digital wave player (The newest Version).
http://www.olympusamerica.com/files/DigitalWavePlayer.zip
4. Install the 2.1.4 vista update
http://olympusamerica.com/cpg_section/software_results.asp?id=1291&os=w
5. Restart the computer.
6. Plug in the VN recorder to the USB port and turn the recorder on.
"Found new hardware" will appear,
7. install automatically.
This may fail, if you see VNUSB device, skip the final steps and proceed to Digital Wave Player to Download files from the Digital Voice Recorder.
If you will see "Other devices" listed in Device manager with "digital voice recorder" underneath it.
8. Right click on the "digital voice recorder"
9. Select update driver from the pop up menu.
10. Choose the browse computer Option
11. In the next window browse to the location that you downloaded the Digital Wave Player application to
12. Click Next
A security warning window will open,
13. Choose "install anyway" and the device will install.
When successfully installed you will see the "other devices" disappear and a VNUSB device with a "VN series device"
underneath it appear at the bottom of the device manager list. There will be a blue question mark next to the device. At this point you can close the device manager and the properties window and open Digital Wave Player. You will see the recorder listed underneath the recorder folder and be able to download and use the program normally now.

SOURCE: my computer does not recognize ny recorder as an external device

Install a VN recorder on VISTA
*************************
1. Make sure the device has been uninstalled in device manager
2. Make sure the old version of digital wave player is uninstalled.
{Delete Temp files in Internet Explorer --Tools--Internet Options --Delete Files-- Delete offline content--OK}
3. Install digital wave player (The newest Version).
http://www.olympusamerica.com/files/DigitalWavePlayer.zip
4. Install the 2.1.4 vista update
http://olympusamerica.com/cpg_section/software_results.asp?id=1291&os=w
5. Restart the computer.
6. Plug in the VN recorder to the USB port and turn the recorder on.
"Found new hardware" will appear,
7. install automatically.
This may fail, if you see VNUSB device, skip the final steps and proceed to Digital Wave Player to Download files from the Digital Voice Recorder.
If you will see "Other devices" listed in Device manager with "digital voice recorder" underneath it.
8. Right click on the "digital voice recorder"
9. Select update driver from the pop up menu.
10. Choose the browse computer Option
11. In the next window browse to the location that you downloaded the Digital Wave Player application to
12. Click Next
A security warning window will open,
13. Choose "install anyway" and the device will install.
When successfully installed you will see the "other devices" disappear and a VNUSB device with a "VN series device"
underneath it appear at the bottom of the device manager list. There will be a blue question mark next to the device. At this point you can close the device manager and the properties window and open Digital Wave Player. You will see the recorder listed underneath the recorder folder and be able to download and use the program normally now.