Windows 7: Win 7 + Older HP Desktop = NO BOOT

I have an old HP Pavillion 751 desktop with a P4 2Ghz. I put a new AGP vid card in and loaded Windows 7 32bit. The OS loaded fine, but the system will not boot at all. It's just a reboot loop. I cannot get Windows 7 to even display on the screen for half second to press F8. I tried doing a startup repair also, but it will not boot. I then tried to load Vista...same exact result. I had XP running fine on here. The HD and RAM are good, no issues there. What is the reason this system will not run with either Vista or 7, even with a brand new 'aero' compatible video card?

Make sure that you have your CD removed. If you have and it still does not work go into bios and make sure it is set to boot from the Hard drive.

Without full system specs its impossible to even begin troubleshooting your problem.... You know what to do.. see the link in my sig....

It's an HP Pavillion 751, see link below. 2Ghz P4, 80GB IDE HD, 1Gb RAM, GForce FX5200 AGP Video. I have set it to boot from the HD and the CD has long since been removed. I am a 16yr IT Pro, so I have done all the basic troubleshooting.
Motherboard description

• Manufacturer's name - ASUS P4S333-M
• HP/Compaq name - Missouri

Motherboard supplierASUSSystem BIOS supplierAsus AwardForm factorUATXProcessor brandIntelProcessor socket typeMPGA478Processor familyPentium® 4 (Willamette, Northwood)Processor front side bus frequency400 MHzChipset nameSiS650Chipset "North Bridge"SiS650Revision/SteppingA1Chipset "South Bridge"SiS961Revision/SteppingA2Super I/O ITERevision/SteppingIT8707Flash BIOS device2MB Flash EEPROMMemory typeDDRMemory speedPC2100 / PC1600Memory sockets2 DIMMMaximum memory2GBGraphics supplierGraphic CardGraphics configurationUp/DownOnboard graphics memoryN/AGraphics connector (AGP)AGP 4XTV-out deviceNoTV-out configurationAGP TV Out CardAudioAC97 DownAC’97 CODEC deviceADI1885Audio jacks (legend below)M, LI, LO, SO, M/GMMicrophoneLILine InLOLine outSOSpeakerM/GMidi/GameEthernet 10/100 LAN supplierSiS 961+PHY ICS 1893

Motherboard Specifications, P4S333-M (Missouri) HP Pavilion 751 CTO Desktop PC - HP Customer Care (United States - English)

Great. Now, add that to the system specs in your profile. That way, people won't have to find the post where you put it.

Done

Did the installer repair console find an OS to repair? What did startup repair report in its log? You need to run it repeatedly if there are multiple issues, and it rarely works when it is offered up first thing.

I would also try unplugging the new video card and use onboard graphics to see if it will startup. You might also try loading the new ATI driver when the installer prompts for drivers at Custom install screen. You should be booting from the installer.

When you say you "loaded" Windows 7 and Vista, are you saying they completed all install steps, or just loaded the files and then failed. At what point during the install does each fail, and what evidence is provided at this failure?

Unplug all your external and internal devices except the graphics card and see if it boots into Windows

If not, remove the lan, wlan connection and boot into Safe Mode (F8)

Go to Device Manager, Display adapter and opt to update the driver, browse for the driver in my computer, let me pick and choose standard vga graphics adapter. Reboot the system

Once at the desktop, go to Control Panel Windows Update and configure Windows Update to download updates but let you choose what to install. Plug in the LAN/WLAN/ connect to the internet (or via modem)

Scan for driver updates on Windows Update and install everything but the graphics driver.

Once everything installs, reboot and continue running Windows Update until it says your system is up to date

Run the Windows 7 Upgrade advisor to see if your graphics card is supported.
a. If not, get a new or used graphics card or just use it as is.
b. If it is supported, install the driver from Windows Update