ok, one last thing before drastic measures.
Follow this path:
C:\Documents and Settings\"user name"\Application Data\Sun\Java\Deployment\cache\javapi\v1.0
and then delete everything that is in the four folders inside of v1.0
There's a good chance your operating system doesn't have this path though.
Also go to:
C:\Documents and Settings\"user name"\Local Settings\Temp
and delete everything it will let you in this folder. Everything if possible
Also delete everything in
C:\Documents and Settings\"user name"\Local Settings\Temporary internet files
there shouldn't be any problems deleting everyting in there. Just hit ctrl A and then hit delete to get it all at once.
If these don't work, It's time for the drastic measures.
Number 1:
If you want to try to solve this problem without visiting the store, you can try this method. (if you decide to do this, reply to me and I will send you a step by step to do this effectively)
Save everything you want to keep that is on your computer on CD's and make sure they work in another computer that has good antivirus and antispyware software - CD's you burn may contain viruses etc. Then, delete everything that is on your computer, but make sure you have the software disks you need to reinstall programs. Then you will need to reformat your Hard drive, which is a touchy process, but if done correctly, is fullproof. Then you can reinstall everything and you will be 100% virus free. But then security updates will be crucial, which are all free and easy to access. You can then either purchase virus software, or use online utilities (microsoft offers one of the best antispyware programs for free, and pandasoft and other sites do a good job of monitering viruses, but without purchased virus software, you won't have realtime protection. (you can always skip from free trial to free trial though

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Number 2
You need good antivirus and antispyware software. Since you can't download anything, go to an electronics store and ask about software. Ask if you can run the software you purchase without connecting to the internet - you should be able to (salemen sometimes try to make you think otherwise) They will no doubt tell you to bring your hard drive in for them to look at, but I would hesitate because you may be able to solve this problem yourself without emptying your wallet. (good ol' forums

)
Then install and run the programs, and the problem should begin to clear up (at least enough so that you could download hotfixes for any major worms or trojans you make have). After that you're home free.
let me know what you decide to do