I am running Mandrake 10.1, kernel 2.6.8, Ndiswrapper 1.1 and a Linksys WMP54G PCI card.

Most of the days it all works like a charm. When I start the PC, it finds the router and it all works like it is supposed to.
The strange thing is that now and then it does not work... Whatever I try on such a day, I can not get a connection to my router. Not even a reboot helps. Booting into Windows (I have that as a backup) works. My wifes PC with XP never has a problem only my box has this strange behaviour. So my conclusion is that there has to be someting in my system that is not working as it should.

Runnig iwlist wlan0 scan on a "difficult day" gives me this list

wlan0 Scan completed :
Cell 01 - Address: 00:30:F1:B7:48:9B
ESSID:"Z10"
Protocol:IEEE 802.11b
Mode:Managed
Frequency:2.452GHz
Quality:0/100 Signal level:-67 dBm Noise level:-256 dBm
Encryption keyn
Bit Rate:1Mb/s
Bit Rate:2Mb/s
Bit Rate:5.5Mb/s
Bit Rate:11Mb/s
Bit Rate:6Mb/s
Bit Rate:9Mb/s
Bit Rate:12Mb/s
Bit Rate:18Mb/s
Bit Rate:24Mb/s
Bit Rate:36Mb/s
Bit Rate:48Mb/s
Bit Rate:54Mb/s
Extra:bcn_int=100
Extra:atim=0

So obviously the linksys card is up and running, and can see the AP

an iwlist gets this ( I took out my WEP key)

wlan0 IEEE 802.11g ESSIDff/any Nickname:"Johan.Z10"
Mode:Managed Frequency:2.462GHz Access Point: 00:00:00:00:00:00
Bit Rate=54Mb/s Tx-Power:16 dBm
RTS thr=2347 B Fragment thr=2346 B
Encryption key:xxxx- xxxx-xxxx-xxxx-xxxx-xxxx-6A Security mode:restricted
Power Managementff
Link Quality:100/100 Signal level:-10 dBm Noise level:-256 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:58 Missed beacon:0

here my ifcfg-wlan0

DEVICE=wlan0
IPADDR=192.168.2.23
NETMASK=255.255.255.0
BOOTPROTO=static
ONBOOT=yes
MII_NOT_SUPPORTED=no
METRIC=10
WIRELESS_MODE=Managed
WIRELESS_ESSID=Z10
WIRELESS_ENC_KEY=xxxxxxxxxxxxxxxx (I have some other values)
NEEDHOSTNAME=yes

commands like
ifup wlan0
iwconfig wlan0 essid Z10
ifconfig wlan0 up
etc, etc...

...does not get me any closer to optaining my IP adress. Only solution is to walk over to the AP and power it off and on agian. When I am back at my PC, it is all working. I dont have to do anything.

Does anyone have a solution to this problem?

I get the same problem. I think it's dhcpcd not releasing the interface correctly at down-time, but I'm not sure. I've tried modifying my network and wireless scripts, but nothing much is helping.
If you use dhcpcd, you could try adding -d to your options in /etc/conf.d/dhcpcd to debug your dhcpcd output - see man dhcpcd for how to get this output logged, mine goes into /var/log/everything.log, but yours will probably be different. I suppose you could do something similar for dhclient if you're using that. If you're connecting statically, then none of this applies.
It's an irritation I'm reluctantly becoming resigned to accepting for the time-being.

What works for me is
# iwconfig wlan0 essid (ESSID name)
repeating until iwconfig shows the correct essid, then
# /etc/rc.d/network start
repeating until the network daemon starts up correctly.

This isn't always necessary, only when iwconfig doesn't pick up my essid correctly at bootup. If you solve this, please post how you did it.
cheers

Thanks for the input. I am not using dhcpcd, but static IP address.
I have tried dhcpcd as well but that does not make a difference

I looked more into my /var/log/messages comparing the one from yesterday, when I did have the problem and today when it all worked and I can not find anything that gives me a clue

It is irritating, and for every new release of ndiswrapper I hope that it goes away.

If I find a solution I will post it here

Johan