xp problem (dont know much about computers)

hello i was wondering if anyone could help me ive been gettig a message upon startup windows is closing with status code 1073741482 i know how to close this (with shutdown - a) but now my antivirus programs are not working,
im running avg ver9 and malwarebytes
avg will not scan at all even in safe more and malbyte says i havent got permission to access it
also my pcs hooked up to an xbox (for internet use) and now xbox says there is a problem connecting to the internet???
if anyones got an ideas id love to hear them but could you please keep them in laymens terms as i dont know a lot about computers
Example had to wiki what malware was!
thanks in advance

 

oh 1 more thing when i push in internet button instead of going to my homepage it goes to google and i cant stop it in the internet options!

 

Hi jakesy, welcome to the forum

You will need to follow exactly the steps listed here for your version of Windows, read each set of instructions carefully and follow them to the letter, noting any error messages at all stages.

Good luck with the fix.

 

done the steps but still got a problem it seemed to clean etc very fast but my antivirus software still wont scan also i now cant download any other files! this is a problem as i dont have access to any other computers ?!?!?! ARGH!

 

Start again from Step 1, read everything carefully, don't miss anything out.