I've got an HP Presaario desktop, running Vista Home Basic. I've had nothing but problems with this computer for two years. I finally figured out part of my problem. I've always done an automatic update. I decided to upgrade to Windows 7 so I downloaded a scanner to determine if my computer is compatible. It showed that I don't have enough RAM and I was missing SP1. In checking my updates it failed to successfully download SP1. Getting that installed help me tremendously. Now I'm trying to add RAM. I bought another stick from Crucial. I've tried to install it and my computer doesn't recognize the second stick. I went thru it with Crucial and HP. I finally got an upper level support person at HP and we were making progress when the battery on my laptop died. I then got back to HP and the person I was chatting with immediatly went to, "you've got a problem on your motherboard send it in and for $280 we'll fix it". I still haven't given up yet. I went down to and talked to the "Geek Squad" and he told me it might be a timing issue between the two sticks. The original is "PC2-4200" and the new one is "PC2-5300". I checked and the machine does have the latest version of BIOS. The computer should be able to support 2GB's of RAM, 1GB original and 1GB from the new stick. Any suggestions before I go and pay to replace the motherboard. One thing I'm wondering is can I replace the original stick with a 2GB stick? By the way, I've had the computer running with either stick in either slot.

So we can take a close look at your system configuration, please follow along below to post a PCPitstop scan for review.

Please Run the PCPitstop Full Tests, here:

Note: Vista users with UAC must first Right-click IE - Select "Run as Administrator"
Register and create a password
Accept the ActiveX component to allow your machine to run the Full Tests
Registering and accepting the ActiveX are both SAFE and FREE.
Full Tests is the first item in the left hand column of that page.

The Full Tests take less than 5 minutes for most machines.
Once you have your Results, please post the TechExpress Link back here into this thread for review.
TechExpress is the sixth item on the list in the yellow box in upper right area of any Results page.
Post the entire URL link information back here into this Forum thread.

Note: Vista users, please close your instance of IE "Rrunning as Administrator" after you are finished reviewing your Results.

Caution: During the testing of Video Adapter, a variety of patterns, shapes, colors and text are “flashed” onto the users monitor screen. In the many thousands of daily uses of the PCPitstop Full Tests over several years, two individuals who suffer epilepsy experienced discomfort and temporary dizziness when viewing the flashing patterns.
If you know that you are susceptible to photo driven seizure, please look away from your screen during the Video Adapter testing sequence.

Note: The PCPitstop Full Tests Results is a free service, but is supported by various paid product advertisements for utilities that "could" remedy the OP's problem.
Since D-A-L is a "free-help" forum, we do not recommend or endorse purchase of automated utilities, and will assist you in manually correcting any problems and settings necessary to optimize your machine's performance. Ask your questions here. We'll help you walk through any necessary steps.

kind regards,

The ram sticks must match in timing. I would take the new back and get a PC-4200 compatible stick.