Major issue with hp zv6008cl laptop

I purchased this laptop pc about 4 years ago. I needed it for work and couple of months after I bought it, the firm decided to install computers on every desk. I took my laptop back home and put it in the closet. I use my DELL desktop all the time and that never gave me a problem. About two years ago I went on a trip to visit the old country and I needed my hp zv6008cl to download some old family pictures on my newly purchased Epson Perfection 4490. After few downloads I started to get this error message: IRQL_NOT_LESS_OR_EQUAL. I could not figure out what caused it to happen therefore I decided to reformat the hd and to installed XP Pro thinking this would take care of this problem. I only had few pictures that I needed to save. I had difficulties during the process of downloading the new OS. Eventually I managed to do so but the problem persisted and after I contacted hp I was told to updated the BIOS. That did not help. I was asked to kill the hd which I did. Then I went and replaced the two sticks of RAM. That did not solve the problem. I replaced the hd. This did not work neither. The geeks at Best Buy checked the system board and told me it was fine. Every time I ran the memory+ RAM test it gave me thousands of errors. I even used one RAM stick one at a time and that did not help. This laptop is driving me crazy. Can any body help me please? hp wanted me to spend $400 to fix it and they are hopeless. I am in the process of installing the XP. Again and after formatting the hd the process stops while the setup is loading files. I keep changing the system to BIOS from CD but it always go back to BIOS from floppy diskette drive when there is no such thing. I removed the small battery to go to default and now COMPAQ logo goes when it should say hp. What a mess! Thank you.

That is what I thought when I ran the memory+ and I was very happy to see the RAM is fried. I went and purchased two stick of ram 1 gig each but that did not solve my problem. still can not download the XP from the recovery disks. I am getting among other things memory_management error. Thank you