messed up my linux desktop display

A few months back I finally renewed my RH subscriptions on five outdated (years without updates) RH installations, that ranged between 5.1 and 5.4. Over the last few weeks I have finally gotten around to trying to register these systems again with the RHN to take advantage of the updates with the ultimate goal of installing 6.3. I did manage to renew the subscription on the 5.4 box and connect to RHN (classic) without too much problem, using Registration_Update-rhel-5.tar.gz and maybe requiring one other rpm. (epel-release-5-4.noarch?) However I was having problems getting/creating certificates to complete the process (via rhn_register) on two other systems running 5.1 and 5.3. (the actual history of what I've done is kind of sketchy since spread out over weeks)

Long story short, having some time yesterday I went back to try to tackle the registration on my office PC (RH 5.3) attempting to load rpms base on the bug fix I think needed the in RHBA-2010:0270. The only issue left was tying to run rhn-client-tools rpm to install by resolving several dependency issues. I had only one complaint left: hal-0.5.8.1-52.el5.x86_64. I noticed the errors in installing this rpm was because another version of hal existed, and naive me figured maybe I just needed to uninstall the older version first via the load software interface. Bad move I guess as I noticed it updated lots of things afterwards and things were a little wonky on the desktop. Bad Move number 2: was thinking maybe I needed to log off and back in to update the desktop. You know the answer- can't get back to the display desktop. I do have the command line, and my files seem to be there. (Fortunately this is my office PC and not one of the boxes that operate instrument systems in daily use!) And I must confess that while I have had my oldest Dell running RH5.3 since 2008, I really don't know my way around linux too well! (as you can probably tell)

So what should I do- attempt to fix this botched up system (with your suggestions on how to do so, of course), or attempt to just copy/backup my files and go straight to the planned upgrade to RH 6.3? (6.3 is the latest tested/supported version of RH by instrument manufacturer for its own software - I guess technically I could go newer on my office PC) Thanks in advance....