mobile version application can run on xp ?

I have problem, I have used firefox 3.0.xx Windows XP version.

But I.m used 3G network connecting internet.
...do you know each KB/MB is cost$

I hope can block image , flash , and changed that browser detect. I.m used [what browser application]

I know how to used Option>Content>Load image automatically disable image,

my question
(1) but flash , where can disable ?

(2) some website can detect I m used what brower application, how to changed that string, I'm used Mobile/Platforms.

(3) https://wiki.mozilla.org/Mobile/Platforms
About Firefox for Mobile , do yo known that mobile application, can used Windows XP system ?

Please!

 

thanks, is look fine, but why now website need more JS, Flash, and image verify...?

my step:
logon yahoo/google mail. and
loading mailbox,
view mail and
reply mail...
image verify
check mail
closed connecting

around used 2MB data . I'm not attect document and check that mail no photo include.


why crazy ?

but disable someone maybe faild.
Image Verify, need enable Image
Send and check mail, that is Javascript(), not true link.