Graphical logon error after apache2 + mysql5 + php5 is installed

The image logon error after apache2 + mysql5 + php5 is installed-Linux Enterprise Application-Linux server application information. For more information, see the following. My first system was installed on the centos5.0 installation disk and then updated to centos5.1 through the source. During this period, the rpmforge software package that supports dag sources is installed. Later, I installed apache2 + mysql5 + php5 through yum, phpmyadmin, and zend by hand. Then, log on to the system again and check that the running of the system is correct. Due to lack of experience, you can reinstall the system and directly install the system on the disk as 5.1. However, you can install the above environment using the source, and you have installed rpmforge before. I have installed all the required modules and logged on again. The X-windows logon screen is changed with no background image. All the text (including Chinese and English letters and numbers) is in a small rectangle. There will be an error report, but the content is also a small square, followed by input, you can log on to gnome normally. After entering gnome, the user environment is normal, but php cannot run normally. I uninstalled the software again through yum, but there is still a problem with logon. Can anyone help me to see what I should do?
My machine configuration: CPU: Pentium 4, clock speed 3.06 GHz, support HT; Memory: DDR2 533 MHz 512 MB
The video card is integrated with the motherboard, and the hard disk is two GB.
Software Installation: gnome Desktop (X-windows of course), Openssh and other related components, vsftpd, arpwatch and related components, firefox2, calmav, openoffice, p7zip, rar, unrar, zip, unzip, mplayer, and required support libraries (but none of the gstreamer-related programs can run, such as totem. I deleted these files in the later uninstallation, however, because gstreamer needs to delete gnome, it is still there), realplayer10GOLD, xine and its related programs, xmms (which can be used normally), and only gthumb is shown in the figure, other texts are edited by vim (learning in progress), nano (used in Terminal), and gedit. Most of the supported gcc on the compiler has been installed, there are also gtk + and gtk2, and other libraries that everyone will use and support the above software. I will not elaborate on them here.
In addition, I opened the SELinux rule, set it to force, and allowed vsftpd to switch to the user's main directory, and the corresponding SELinux settings of httpd, but I don't know if there is anything wrong with it, please advise. Thank you!