Go to the
Adobe page hosting the removal tool and download it.
Close all browsers. Run the tool. (Although not prompted to, I usually reboot at this point.)
Then go
Here and download/install the flash player. (I suggest you do not include the free security scan that installs with it, unless you opt out.) Do this for each browser you use. At some point when installing in IE, it will tell you to close the browser to finish the installation.
Depending on the type of firewall you use, you may be prompted for certain files or reg entries to be modified.