I have a brilliant  Inspiron 1525 laptop and running Windows Vista.  

Turning on laptop this morning there are three windows open called Computer, Network and Public panes. These windows I did not open myself when on the computer last night and they will not close, is it a virus? There are also some different bars for viewing stuff like dropdowns in the bottom toolbar (quicklaunch toolbar?) that I did not see like this before.

Last things I done the last few days:

1. Last night I downloaded two job documents from a NHS jobs website. Perhaps could i have got a virus from one of those downloaded file? 

2. Recall I may have took advantage of a free virusscan with McAfee which popped up window yesterday. even though I already have a free a.v. program I am using for now.  It makes me think could it have been a scam window?

Anyway I immediately did a system scan using my Avira antivirus. It did not detect anything but during the clean up a window flashed up saying "security options failed" with an ok box to click on which i did.  Could I have been the victim of a hacker attack last night because I don't run full a.v. software with a complete firewall on (instead I opted to put the Windows standard firewall in place.) I realise McAfee is probably a good detector and a.v. software I downloaded from Dell Support centre and currently ran it through the C: and related - it says No Virus Threat present.

Over the last few days I have received prompts to update my Firefox browser software (3.0.15 currently) to 3.5 version.  Says I may need to update the version for security reasons as well as others. I was going to do this but was aware there could be problems with extensions, So i waited to read up on this.  Do you think it would be ok for me to upgrade my Moxilla after this is all remedied, or do you think I need to do it quickly as there has been a security hitch with current version?

I think it also prompted my Adobe flash needs attention, I not sure if I have upgraded this or not currently, and need to check..

The version of Internet explorer I am using is currently 8.

Please advise me immediately what do you think I should do next to limit further damage and fix this fault? I am not very techie but i do know how to download programs, move things around drives etc. Need some expert advice ASAP please.

Many thanks cc

(A normally cautious PC user.)