I use Firefox bouth in WindowsXP and in Fedora Core 5. As usual, in Windows-word no problems. In Fedora Core Firefox works otherwise well but untill recently I have not gotten  Flash Player plugin to install. I found some advice and did everything asked (a long list follows):

[fossiili@localhost ~]$ su -
Password:
[root@localhost ~]# yum install flash-plugin
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
livna                                                                [1/7]
livna                     100% |=========================|  951 B    00:00
flash                                                                [2/7]
flash                     100% |=========================|  951 B    00:00
core                                                                 [3/7]
core                      100% |=========================| 1.1 kB    00:00
jpackage-fedora                                                      [4/7]
jpackage-fedora           100% |=========================|  951 B    00:00
jpackage-generic                                                     [5/7]
jpackage-generic          100% |=========================|  951 B    00:00
extras                                                               [6/7]
extras                    100% |=========================| 1.1 kB    00:00
updates                                                              [7/7]
updates                   100% |=========================| 1.2 kB    00:00
Reading repository metadata in from local files
primary.xml.gz            100% |=========================| 148 kB    00:02
livna     : ################################################## 454/454
Added 9 new packages, deleted 4 old in 0.71 seconds
primary.xml.gz            100% |=========================| 5.7 kB    00:00
jpackage-f: ################################################## 25/25
Added 0 new packages, deleted 0 old in 0.11 seconds
primary.xml.gz            100% |=========================| 366 kB    00:06
jpackage-g: ################################################## 1597/1597
Added 0 new packages, deleted 0 old in 1.20 seconds
primary.xml.gz             100% |=========================| 1.4 MB    00:23
extras    : ################################################## 4749/4749
Added 202 new packages, deleted 111 old in 8.51 seconds
primary.xml.gz            100% |=========================| 372 kB    00:06
updates   : ################################################## 1005/1005
Added 15 new packages, deleted 71 old in 3.21 seconds
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for flash-plugin to pack into transaction set.
flash-plugin-7.0.63-1.i38 100% |=========================| 6.0 kB    00:00
---> Package flash-plugin.i386 0:7.0.63-1 set to be updated
--> Running transaction check

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 flash-plugin            i386       7.0.63-1         flash             998 k

Transaction Summary
=============================================================================
Install      1 Package(s)
Update       0 Package(s)
Remove       0 Package(s)
Total download size: 998 k
Is this ok [y/N]: y
Downloading Packages:
(1/1): flash-plugin-7.0.6 100% |=========================| 998 kB    00:16
warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID 8df56d05
Public key for flash-plugin-7.0.63-1.i386.rpm is not installed
Retrieving GPG key from http://macromedia.mplug.org/FEDORA-GPG-KEY
Importing GPG key 0x8DF56D05 "Fedora Linux (RPMS) <security@fedora.us>"
Is this ok [y/N]: y
Key imported successfully
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing: flash-plugin                 ######################### [1/1]

Installed: flash-plugin.i386 0:7.0.63-1
Complete!
[root@localhost ~]# mkdir -p /usr/X11R6/lib/X11/fs/
[root@localhost ~]# ln -s /etc/X11/fs/config /usr/X11R6/lib/X11/fs/config
[root@localhost ~]#

But this did not help :(

I know, this is Linux world, but I did not want to change back to Windows when I need Flash Playing.