Windows XP takes forever to install

(Dimension 4600 series)

This computer was a gift and has turned into a project:emotion-7:......The first issue was a stop: 0x00000024 bsod,it was a failing HDD and has been replaced,also had 2 sticks of bad memory (1g each),running 512 mb of memory now,I did test it with memtest,tested good(512)=(2X256),and to verify I pulled the same type of memory from my Optiplex and no difference, the issue Im having is it took 6 hours to try and install XP and I finally gave up,I've also tried running (Ubuntu) "live" from the CD,Hardy Heron,Lucid lynx,Lubuntu 10.04,Fedora 14 LXDE and Mint 9 LXDE......they just wont run Live,Sounds like bad memory....but like I said I tested the 512 and also pulled a 1g stick from my Optiplex,doesnt make any difference,

I ran the Express Test from the Diagnostics and utilities CD that came with the computer and within 5 seconds I get this:

I select Yes,continue and then I get this:

I click OK,and the computer reboots..................any Ideas?

I believe I found the culprit,in Bios,my CPU speed was set at "Compatible",I toggled it to "Normal",Im currently running the Express Test....so far so good,will keep you posted.Express Test finished with no problems.

Lubuntu loads up fine now,will try to reinstall XP,when I get a chance.Shouldnt be an issue now.