a friend is getting an error message do you know what this means?

my friend is has an older p2 400 laptop that he did a fresh install of xp. he keeps getting this error message evertime he logs onto the internet. it says LSA Shell had and error and had to be closed, then a different message comes up and says that there is an error with C:windows/system32/LSASS.EXE and windows will restart and it counts down from 1 minute and then restarts the computer. got any ideas what going on?

ps the laptop had xp install previous and running great for a yr or 2 then about 6 months ago all **** it the fan and it stopped working right. at one point he said so many pop ups would come up and freeze. he got a spyware and pop up killer and that helped but still this were tweaked out so thats why we did a fresh install of windows.

check this... its a worm

http://it.trendmicro-europe.com/enterprise/security_info/ve_detail.php?id=58928&VName=WORM_SASSER.A

and how to fix it if you don't like the above one: http://www.blackviper.com/AskBV/tech10.htm

ok so why did it start doing this only after i re-installed windows after a full format of the hard drive? and why is it not doing anything now that i changed drivers for the modem?

When you reinstalled windows, you probably didn't have time to get the critical update before the worm infected the PC once you got on the internet.

The worm doesn't always cause that message to show up, it only does so when it overloads the process that you get that message. It can happily live and work without causing that message to pop up again.

wow really. well after several fresh installs of xp i brought it to my house and installed xp again. this time i think i installed everything including mcafee and i have not seen that malware program and there have not been any messages so i think its save to say problem solved. thanks for you help in these matters,
al