You have the Blaster virus
The FIRST thing you need to do is ensure that you have installed ALL Microsoft Updates.
SECOND:This is an ABSOLUTE PRIORITY,get a good firewall,read it's documentation so you know how to set it up and make sure it starts on bootup.
An excellent FREE firewall,called ZoneAlarm,can be found here:
http://www.uant.net/firewall/zonealarmguide.html
THIRD:Another ABSOLUTE PRIORITY is to get a good Antivirus program and AVG is as good as it gets.You can get a free copy here:
http://www.grisoft.com/us/us_dwnl_free.php
(I use these 2 programs on my machine and have had no virus,trojan,worm or browser hijacking in over a year)
Spybot Search & Destroy is a free program that does a good job and can be found here:
http://www.safer-networking.org/index.php?page=download
Another thing you can do is an online system scan from here:
http://housecall.antivirus.com/housecall/start_corp.asp
FOURTH:Before running ANY scan for virus,trojan,worm etc. you should ALWAYS turn off System Restore as copies of everything you are trying to get rid of are in System Restore just waiting for you to put them back where they came from in the first place.
This will delete all restore points on your machine,but if they are infected you don't want them anyway.
FIFTH:Another good thing to do before running the scans is to clear out your TIF and other temp files.
In Internet Options, under the General tab click the Delete temporary internet files, choose to delete all Offline content.
Also, go to Start - Search - Files or folders - in the "All or part of the file name" box, type: *.tmp and choose Edit - select all - File - delete.
Do the same for "Cookies"
Empty the contents of the C:\Windows\temp folder and C:\temp folder, if you have one.
Empty Recycle bin.
SIXTH:Now you are ready to scan your system using the above listed Spybot and Housecall
Make sure that you update antivirus,firewall and scanning programs on a regular basis,and particularly,just before performing a system scan.
Once you have cleaned your system and have it running the way it should,turn System Restore back on and create a fresh,clean restore point.