After upgrading my Acer Aspire 4810T to Ubuntu to 13.04 32bit connection to any wi-fi (or Ethernet) usually fails. Sometimes, maybe once in five tries, rebooting may resolve the problem. Contrary to some other related posts, the proximity of the wifi station doesn't seem to have an impact on the problem.

The wi-fi application indicator in the notification area at top bar of the screen keeps on entering and exiting and the whole system gets very slow. When I click any application indicator their menus often appear empty. Running any program usually quickly freezes the whole system which makes searching the culprit from logs very challenging.

My network card is: Intel WiFi Link 5100 AGN.

The same laptop worked fine with previous Ubuntu version and at the moment it works fine with Windows Vista. With Virtualbox and Windows Vista as a host and 13.04 as a guest it works ok, though slowly.

dmesg shows a long list of network-manager kills and respawns

[ 33.224314] init: network-manager main process (862) killed by ABRT
signal [ 33.224361] init: network-manager main process ended,
respawning [ 33.709347] init: network-manager main process (1307)
killed by ABRT signal [ 33.709393] init: network-manager main
process ended, respawning

apport-unpack shows that the NetworkManager has Crashed (ProcCmdline and ProblemType)

apport-unpack also shows warnings in WiFiSyslog

/sys/devices/virtual/net/lo: couldn't determine device driver;

ignoring.. Trying to remove a non-existant call id.

and hints for a firmware bug

May 1 15:31:49 sauli-Aspire-4810T kernel: [ 614.465977] atl1c
0000:01:00.0: vpd r/w failed. This is likely a firmware bug on this
device. Contact the card vendor for a firmware update.

Any suggestions, where to start looking for the real problem and how to correct it?