One of the differences between Firefox's "Safe Mode" which you tested is that hardware acceleration of graphics is turned off in Safe Mode. It's hard to see how that would affect forms, but you certainly could try disabling it in normal mode.

You usually need to restart Firefox in order for this to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.).

orange Firefox button or classic Tools menu > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

Do you have any privacy/security software installed that could affect keyboard entry on secure sites? Some users have reported problems with the Comcast/Xfinity "Constant Guard" Protection Suite component named Identity Guard, which apparently tries to scramble keyboard input to frustrate keyloggers.

Note that Safe mode also disables the JavaScript JIT compiler, so there may be JavaScript involved.

• javascript.options.methodjit.content

Do you see any errors in the Error Console?

You can hide the CSS errors that usually fill that window.

Thanks Jcher2000 and cor-el for your suggestions, I think have solved the mystery, Firefox add-ons were all ok, but EXTENSIONS contained a program called Price-Peep which has caused the problem. Solved by elimination; Shut down ALL Add-ons AND extensions, Hotmail worked, re-introduced all Add-ONs, one at a time, all worked OK, then did the same with extensions, worked down the list and, at the second to last (how unusual), Hotmail stopped working with Pricepeep enabled, then restarted with it Ppee disabled, checked the last program and all still working in Hotmail. I have just looked at the Pricepeep site and I think it was added when I took delivery of a spare webcam which didn't have software so downloaded software from the web (cannot check back site as have cleared all history caches in sorting this mes) so ise people NOT to agree to download this crap. Just emailed the idiots )© 2012 Verti Technology Group). Now, how do I report this to Mozilla and Hotmail ?... Thanks folks, from a very pissed off person in France...Colin.