[Avoireeideree]

No point in virus scanning or any thing like that as its never a virus, this applys for deleting cookies, preftech files and defragging harddrives there ust placebos to make yu think things are better when often they make things worse

If using firefox best to unistall flash and reinstall with the latest version or alternatively for ease just install the latest flash

here: Adobe - Adobe Flash Player

If problem persists then a fresh install of firefox is needed or alternatively a change of browser, though when unistalling firefox make sure all registry keys and all asociated files are wiped of the disk before re-installing