I HAVE GOT ONE HP DESKTOP MACHINE IT SHOWS THAT PARITY ERROR AT THE TIME OF STARTUP BY PRESSING F1 IT WOKS WELL I THOUGHT THAT ITS PROBLEM FOR MEMORY, I TRIED BY CHANGING RAM BUT IT GIVES THE SAME PROBEM PLEASE HELP ME OUT

try this startup-repair from WINDOWS RECOVERY-PARTITION tap on F9,F10,F11 OR DEL when windows boot one tap every second.
or you can run SFC / SCANNOW from the command prompt as a ADMINISTRATOR

This is ith the RAM in the omputerin the giving you thqt defect. replae the RAM and it will fix the problem.

NMI parity error (Non-maskable Interrupt) is generally a motherboard or a RAM issue.
You can try flashing the BIOS to A04 (You'll need to copy the flash executable to a bootable CD or bootable USB drive to run the flash.
Try individual or different RAM modules
if all those do not resolve, issue is most likely the motherboard.

Most probably your system is not getting your BIOS settings from your mainboard due to CMOS battery failure.

Check your CMOS 3.0v battery & replace it. Then reconfigure your BIOS settings from the CMOS setup.

Hope it helps

Try this links:
Troubleshooting No LED Lights Glow During Startup or Boot HP Notebook PCs - Troubleshooting Blink Codes or Beep Codes that may Occur During Startup or Boot , or BIOS Beep Codes - For Hp and Compaq Desktop Computers (United States - English) Troubleshooting Black Screen with no Error Messages that may Occur During Startup or Boot HP Notebook PCs - Troubleshooting Black Screen Error Messages that May Display During Startup or Boot HP Notebook PCs - Troubleshooting Blue Screen Error Messages that May Display During Startup or Boot HP Notebook PCs - Troubleshooting Windows Logo Screen Error Messages that May Display During Startup or Boot Using HP Support Tools to Update HP Software, Drivers, and BIOS with Windows 7 . Using HP Update Tools to Update HP Software, Drivers, and BIOS with Vista Updating the BIOS or ROM for Notebooks Running Windows XP Updating Drivers and Software with Windows Update

update the bios.Find out the motherboard number.
than go there http://downloadcenter.intel.com/Default.aspx
find the bios and install it.Take care with that.Do not shut down under
the install process...

my computer when started then show 1801microcode update error and press f1 then continue windows 7styler how i can solve this problume

This is a bios issue... Most likely you need to press F1 and then Save and Exit and will go away... Sounds like a checksum error or something is off in the BIOS and it is letting you know ; )

Hi Robert,
please try these troubleshooting steps,
Resolving the blank screen Follow the instructions below in order to fix this issue:

1. Remove any CDs, DVDs or memory cards from the computer.
2. Disconnect all devices from the computer leaving only the original mouse, monitor and keyboard and power cord connected.
3. Restart the PC. NOTE: If this resolved the issue, see the Preventing the blank screen section at the end of this document.
4. Press the F1 key repeatedly during the first startup screen until the entering setup message appears.
5. Press the F5 key to restore the default settings. Use the arrow keys to select YES and press ENTER .
6. Press the F10 key to save the changes and exit. Use the arrow keys to select YES and press ENTER . The PC restarts.
7. When the system restarts select Last Known Configuration from the boot menu. The PC should now startup normally. If the blank screen persists continue with the following steps.
8. Select Safe Mode from the Windows Advanced Options Menu .
9. Use Microsoft's System Restore feature to restore your computer to an earlier time and correct the issue.

Have you tried changing the cmos battery on the motherboard?