i need help with my memory

[darknate]

i started getting this message a couple of months ago and then it went away but now it's back. here is how it goes. the title is Isass.exe-Application Error . and followed by the title, it says:

The instruction at "0x900d089b" referenced memory at "0x900d089b." the memory could not ge "read."

then i click ok and it goes to this

title is: The system process

followed by: 'C:'Windows/system32/Isass.exe' terminated unexpectedly with status code 128. and then it has a timer for 1 minute and once it's up, it shuts down automatically and restarts.

any ideas on what this is?

 

[Peddant]

You have the Sasser worm.

Go HERE and follow the instructions.They include downloading the MS update and the removal tool.
The update can also be found HERE Turn off System Restore first.

If the system reboots before you are able to download and install the patch,the
shutdown utility can abort a shutdown that is in progress (counting down).
This utility is part of Windows XP.

Click START, RUN Type SHUTDOWN -A and hit ENTER

Try to keep your system firewalled and updated in future