SOLVED wireless card problem: ubuntu i386: ERROR SAID: SIOCSIFFLAGS: Device or resource busy

STEP 1: Is there a wireless network card present? YES: see list hardware:

#lshw -C network
driver=rt61pci
*-network DISABLED
description: Wireless interface
product: RT2561/RT61 802.11g PCI
vendor: RaLink
physical id: 1
bus info: pci@0000:11:01.0
logical name: wlan0
version: 00
serial: 00:08:a1:be:9a:67
width: 32 bits
clock: 33MHz
capabilities: pm bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=rt61pci latency=32 multicast=yes wireless=IEEE 802.11bg
resources: irq:0 memory:fc500000-fc507fff

STEP 2: Is there a driver module loaded for the RaLink RT2561? YES: list modules:

#lsmod | grep -i RT
rt61pci 18920 0
crc_itu_t 1371 1 rt61pci
rt2x00pci 6027 1 rt61pci
rt2x00lib 27541 2 rt61pci,rt2x00pci

STEP 3: Can I bring it up? NO: this is the error message:

#ifconfig wlan0 up
SIOCSIFFLAGS: Device or resource busy

==> Here is the solution, that finally worked for me.
This was posted by another kind linux user:

open the computer
take out the wireless PCI card
boot
shutdown
put the wireless card back in
boot