Did you try another client PC?
If the problem is not specific to the client I would conclude that your server or network is having problems.
* Check your NIC's operation speed (10MBits?, 100MBits, ...)
* From the consol or remote desktop, how is the general performace of your server?
* Try copying a large file from the shares to the desktop. Normal tranfer speeds?
* Check your cabling.
- Theo.
No home server like Home Server