For one thing, you're pushing the envelope when it comes to system specs with regards to GNOME. This could be part of the problem. XFCE or LXDE are lighter and may be more suitable for your machine, but of course it's up to you.
Basically what you need to do is go through and install each upgrade individually. It's a pain in the butt, but it will help you to pinpoint the problem. Your machine will be borked when you install the "bad" package that's causing the issue. From there you can log in using Failsafe mode and, using the CLI, remove the "bad" package. You should be able to replace it with the older version that worked but I will need to do a little more research on just how to go about that.
Let me know if you run into trouble.
If it helps here is my updated "chkconfig --list", as of 07/17/2010:
I've noticed that there's nothing on there referring to HP. I don't know what else is missing or shouldn't be on the list. Somebody please help me! I really need to get this computer set up to apply for jobs, and for medical, health and legal research. Thank you ALL for ALL of your help.
chkconfig --list
acpid 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:on
alsa 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
apmd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
apmiser 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
atd 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:off
atieventsd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
avahi-daemon 0:off 1:off 2:off 3:on 4:off 5:on 6:off 7:off
bpalogin 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
crond 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
cups 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
dm 0:off 1:off 2:on 3:off 4:on 5:on 6:off 7:on
haldaemon 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:on
ibod 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
ip6tables 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
iptables 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
irqbalance 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:off
kheader 0:off 1:off 2:on 3:on 4:off 5:on 6:off 7:off
laptop-mode 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
mandi 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
messagebus 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:on
msec 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
mtinkd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
netconsole 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
netfs 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
network 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
network-auth 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
network-up 0:off 1:off 2:off 3:on 4:off 5:on 6:off 7:off
nfs-common 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
nfs-server 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
ntpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
numlock 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:on
oki4daemon 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
partmon 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
portreserve 0:off 1:off 2:on 3:off 4:on 5:off 6:off 7:off
pppoe 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
pptp 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
resmgr 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
resolvconf 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
rpcbind 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
saslauthd 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:off
shorewall 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
smb 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
snmpd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
sound 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
sshd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
syslog 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:on
udev-post 0:off 1:on 2:on 3:on 4:on 5:on 6:off 7:off
ultrabayd 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
uuidd 0:off 1:off 2:off 3:on 4:off 5:on 6:off 7:off
winbind 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
wlan 0:off 1:off 2:off 3:off 4:off 5:off 6:off 7:off
xfs 0:off 1:off 2:on 3:on 4:on 5:on 6:off 7:off
xinetd 0:off 1:off 2:off 3:on 4:on 5:on 6:off 7:off
xinetd based services:
cups-lpd: off
rsync: off
saned: on
sshd-xinetd: off