Sp2 shouldn't be installed until no malware exists on the computer. Malware presence can cause all kinds of problems with SP2 functionality.
In any case, you are right to start attempting to remove the malware that resides in the computer.
Here are some anti-malware tools to have in the toolkit:Freeware AntiSpyware and Security ProgramsSoftware firewalls with freeware versions
(Run only one and disable the ineffective Windows XP firewall)
ZoneAlarm (freeware) V. 6.1.744:http://www.download.com/ZoneAlarm/3000-10435_4-10039884.html
(you can have only one software firewall running. More than one will conflict)Antivirus programs - freeware
(you can only use one resident anti-virus program on your computer. More than one will conflict)
Avast Anti-virus freewarehttp://www.komando.com/bestshareware.aspAnti-malware freeware
(You can run as many of these as you wish. Generally there is no conflict between these and you should always run several since each may find malware that the others may not find)
Ad-Aware SE Personal - freeware http://www.lavasoft.com/
Click on Adaware SE Personal in “Products” on the left side of the page
Or it may be easier to find it here:http://fileforum.betanews.com/detail/Adawa...nal/965718306/1
Spybot S&D: http://www.safer-networking.org/en/index.html
Be sure to enable “Teatimer” which gives you realtime protection against malware invasion. (absolutely necessary)
Microsoft Windows Defender http://www.microsoft.com/athome/security/s...re/default.mspx
This also provides realtime protection. (absolutely necessary)
Microsoft Malicious Software Removal Tool (Win XP and Win 2000):http://www.microsoft.com/security/malwareremove/default.mspx
A˛ - Free from http://www.majorgeeks.com/download4281.html
. Run it, click Search for Updates, then click Scan.
CW Shredder removes some variants of spyware known as the Coolwebsearch Trojan. The Trojan takes advantage of a flaw in a key component of Windows -- Microsoft's version of the Java Virtual Machine -- to install itself via popups often found on porn and illegal software (a.k.a. "warez") sites. Run CWShredder after installing, and have it look for updates. Then click the "Fix" button, and the program will both scan and fix any problems it finds. If your system does not have this kind of spyware, it will give you the good news.
Ccleanerhttp://www.ccleaner.com/Web based online Antivirus and anti-malware scans:
(these can be run regardless of whatever else you are using. You must use Internet Explorer to run these as they require ActiveX to function.)
Kaspersky Anti-Virus Web Scannerhttp://www.kaspersky.com/service?chapter=161739400#betatest
File scanner and virus scannerhttp://www.kaspersky.com/scanforvirus
Panda Activescan http://www.pandasoftware.com/activescan/co...n_principal.htmhttp://www.pandasoftware.com/products/activescan.htm
Trend Micro antivirus and malware scan:http://housecall-beta.trendmicro.com/en/st...orp.asp?id=scan
Etrust Anti-virus web scannerhttp://www3.ca.com/securityadvisor/virusinfo/scan.aspx
Avast Online scanhttp://onlinescan.avast.com/
F Secure online scanhttp://support.f-secure.com/ols/start.html
More AV scans:http://security.symantec.com http://housecall.trendmicro.com http://www.coledata.com/virusalert.htm http://www.cybertechhelp.com/html/misc/av.php http://www.pandasoftware.es/activescan/activescan-com.asp http://www.ravantivirus.com/scan/ http://www.bitdefender.com/
Trojan scans –
Windows Security Trojanscanhttp://windowsecurity.com/trojanscan
See instructions for it here:http://www.windowsecurity.com/trojanscan/trojanscan.asp