computer has mal-ware can not get rid of. need help Please

my computer has mal-ware, screens keep freezing up. I ran rkill and MBAM but still having issues. firefox will not run.

This log file is located at C:\rkill.log.
Please post this only if requested to by the person helping you.
Otherwise you can close this log when you wish.

Rkill was run on 07/31/2011 at 13:53:12.
Operating System: Microsoft Windows XP

Processes terminated by Rkill or while it was running:

C:\PROGRA~1\Yahoo!\MESSEN~1\ymsgr_tray.exe

Rkill completed on 07/31/2011 at 13:53:24.

Malwarebytes' Anti-Malware 1.51.1.1800
www.malwarebytes.org

Database version: 7339

Windows 5.1.2600 Service Pack 2
Internet Explorer 6.0.2900.2180

7/31/2011 1:18:12 PM
mbam-log-2011-07-31 (13-18-12).txt

Scan type: Full scan (C:\|)
Objects scanned: 314871
Time elapsed: 2 hour(s), 3 minute(s), 44 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 1
Registry Values Infected: 0
Registry Data Items Infected: 2
Folders Infected: 0
Files Infected: 0

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
HKEY_CURRENT_USER\SOFTWARE\mdnkso81qq2 (Trojan.FakeAlert) -> Quarantined and deleted successfully.

Registry Values Infected:
(No malicious items detected)

Registry Data Items Infected:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\AntiVirusDisableNotify (PUM.Disabled.SecurityCenter) -> Bad: (1) Good: (0) -> Quarantined and deleted successfully.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\FirewallDisableNotify (PUM.Disabled.SecurityCenter) -> Bad: (1) Good: (0) -> Quarantined and deleted successfully.

Folders Infected:
(No malicious items detected)

Files Infected:
(No malicious items detected)