Ad hoc connection. Need help!

Have two computers: Desktop running Windows XP Professional SP2, with Ethernet connection to Internet, plus with a wireless network card D-Link DWL-G550, and a laptop Compaq nc 6400, running Windows XP Professional SP2, with Wi Fi module installed.

I have set up an ad hoc (computer-to-computer) Wi Fi connection, where Desktop IP is set to 192.168.0.1, and Laptop IP is set to 192.168.0.2 Connection uses WEP security.

When desktop is running and I boot up laptop, they establish Wi Fi connection and I can use it, I can browse Internet, etc. Yet in 5 to 20 min time Wi Fi disconnects, and while desktop tray icon shows that it disconnected, laptop Wi Fi tray icon still shows that it is connected, but obviously no connection exists. I can’t access desktop, or use Internet. After this disconnection I can’t bring up the Wi Fi network dialogue box by double clicking the Wi Fi connection icon in the tray. The only way for me to re-establish the connection is to re-boot the laptop. When I try to re-boot, laptop freezes in the process of shutting down for restart. Then it displays a message that this tray icon for Wi Fi network is not responding. After I click “end task” it continues to shutdown for restart. After I restart connection gets re-established… just to die in 5 to 20 min. Can’t figure this one out.

Please, help me understand why this connection dies. And why Wi Fi freezes on the laptop as a result? I would love to make this ad hoc connection work. Please, do not offer to set up an AP. I am not interested in this (unless you prove to me that I can’t do without it AT ALL). Thanks a lot!! Any help and ideas are appreciated!