To get rid of Blaster:
First Start, Run and type
and click OK. This will give you more time.
Next, get the MS Patch. Without it you'll be reinfected every time you connect: click here
Then run either Stinger click here or the Norton removal tool click here
Your other problems are likely to be spyware-related - run Ad-aware click here and Spybot click here and, if they don't work, CoolwebShredder click here
Then protect against spyware using click here