This is an old thread. Blaster worm should not be an issue in any machine that has current Microsoft updates as their monthly Malicious Software Removal Tool dealt with it ages ago, but I suppose variants could appear in the wild at any time.
Other remedies have been mentioned above.
If you are really concerned run Hijackthis and post its log on one of the following forums for expert advice.
Do not post Hijackthis logs here, we can't help you with those !
Post the logs at a specialist Forum:
Be sure to read all the sticky announcements/instructions at the top of each malware forum!
Peter is correct when saying “…I suppose variants could appear in the wild at any time.”
Ok, let's per share.
I guess the detection of W32/Blaster.worm has been made by your McAfee AV product, correct ? I’m asking it because there are myriad names for threats and each company, when they discover detection, gives a threat a name. Often more than one company will "discover" the detection at about the same time, and a virus will get different names from different companies. So what one company would detect something as may differ significantly from what another company will detect it as.
You said you are using a McAfee Total Protection upgraded a month ago. Are your both Engine and DAT files up to date ? This is very important, as we have hundreds of new malware and malware variants daily. It is also extremely recommended that you have your system patched.
Regarding “Prefetch”, they are not directly executable files, and though they may be related to a virus or trojan file, they are not, on their own, malicious in nature.
"Prefetch files are essentially a resource list. Any time a program is executed, Windows XP will attempt to find a pre-existing prefetch file, and if it's available, it will use it to make the application load up faster. The file will also be updated after it is accessed, so that the more an application is used, the bigger the drop in loading time (to a point). If the application doesn't already have an associated prefetch file, Windows XP will create one. Those files are stored in the \%windir%\prefetch directory."
Quote From Filext.com.
Based on it, I would like to suggest you to run our standalone tool - Stinger - available at http://www.mcafee.com/us/downloads/free-tools/stinger.aspx.
Our FakeAlert Stinger tool is available at http://www.mcafee.com/us/downloads/free-tools/fake-alert-stinger.aspx.
Hope this helps!