There's a strange icon sitting at the top of my screen, and when I go to click on it, it disappears. It's followed by garbled letters which change as Iat is it?

That sounds suspicious. Does this only appear when you are using Firefox, or does it stay on the screen even if you minimize or close Firefox? Since this could be generated by an add-on, here's my suggested procedure for tracking down and cleaning up unwanted add-ons. I know it seems long, but it's not that bad. (A) Open the Windows '''Control Panel''', Uninstall a Program (on XP: Add/Remove Programs). After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. (XP might not have column sorting, but you could try the sorting box with "last run") This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. ''Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it.'' Take out as much trash as possible here. (B) Open Firefox's '''Add-ons page''' using either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons * in the Windows "Run" dialog, type or paste <br><code>firefox.exe "about:addons"</code> In the left column, click '''Plugins'''. Set nonessential and unrecognized plugins to "Never Activate". In the left column, click '''Extensions'''. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions. ''Bear in mind that all extensions are optional, none come with Firefox.'' Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. Any improvement? If you have some additional time: (C) You can search for remaining issues with the '''scanning/cleaning tools''' listed in our support article: [[Troubleshoot Firefox issues caused by malware]]. These on-demand scanners are free and take considerable time to run. If they finish quickly and especially if they require payment, you may have a serious infection. I suggest the specialized forums listed in the article in that case. Success?