Problem with windows firewall

K...my friends firewall isn't working and i cant figure it out. He has had alot of issues with it in the past but is now running smother than it had before, however he can not turn on the windows firewall (also his PC wont show up on networks). I myself have tried everything i can think of. He is logged on as the administrator and has no other firewall running to prevent the windows firewall from working. If you try to turn on the firewall it asks something about turning on something, when you click yes there is an error message. i know im not 100% specific but this is a last second post and im sure its happened before so you might know what im talking about. so i will be posting the error message and any other info you need as soon as i can. i have access to the laptop so i will be able to fix it for him. please help.

Also the computer is running XP SP3.

Well we will check out the basics first

Start->Run-> Control Userpasswords
Confirm that your account is a Computer administrator

Start->Run-> services.msc
Maximize the Services Window that opens
Scroll down to Windows Firewall
Double click on Windows Firewall
Confirm it is set to Automatic
Start it
Close the Services Window

Then go to Start->Run-> firewall.cpl
Confirm Windows Firewall is on


Edit: I decided to expand the help

If the above does not fix the fault

Start->Run-> services.msc
Maximize the Services Window that opens
Scroll down each of the following Services
Confirm all are in Automatic and started

Event Log
Remote Procedure Call (RPC)
Windows Management Instrumentation

Close the Services Window
Then go to Start->Run-> firewall.cpl
Confirm Windows Firewall is on


Still not working?

Start->Run-> CMD
On the command line type:
netsh Winsock reset
And then press Enter
Restart


Still not working?

Go here: http://windowsxp.mvps.org/repairwmi.htm
And Rebuild the WMI Repository
You may need your Windows Setup CD
Restart


That should fix it
If not, then you likely have malware
UPDATED 8-step Viruses/Spyware/Malware Preliminary Removal Instructions