Screen goes black after Windows Vista boot

Try this link, looks like you need to repair boot:
http://h30434.www3.hp.com/t5/Notebook-Lockups-Freezes-Hangs/HP-G72-b66US-Notebook-PC-Dosn-t-Boot-into-Windows/m-p/1336579#M22150

Try this:

If you're booting up the device and it goes thru the Post test and then goes to a black screen this usually means your OS has crashed.
You will need your Operating system or Recovery Disk.
I hope you've backed up your data and files.

Try this:

Windows 7
http://pcsupport.about.com/od/toolsofthetrade/ss/windows-7-startup-repair.htm

Vista:
http://pcsupport.about.com/od/toolsofthetrade/ss/windows-vista-startup-repair.htm

XP:
http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm

Good Luck!!

Reinstall your operating system.

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

Your boot menu for Windows is corrupt. Try to boot from the windows installation disc and make sure to key any key when told to boot off the disc. Once the windows files load, you will have a choice of what to do next. If you have XP, choose the repair option and you will be faced with a black DOS screen...after the blinking cursor type

FIXBOOT hit enter
Try to boot the computer without the disc in it. If it does not boot, then boot off disc again and this time type:

FIXMBR hit yes and enter

Try once again to boot without the disc.

Also try to boot into safe mode by tapping F8 when you see the Compaq name come up during starting. If you can get to the multiple boot up option screen, scroll to "Safe mode with networking" and choose that. If it boots then you can go to the start button > accessories > system tools > system restore > choose a restore point back a day or two and follow the prompts.

If you have Vista, boot off the disc and choose start up repair. If that doesn't work, boot again and choose restore computer to an earlier time. Again choose a restore point back a few days. Good luck ParrotHead PC Repair

try to boot the computer using the recovery disc in it, sounds like some operating system files are gone or corrupted, booting from the disc should reinstall the os, or the missing files, but it will check for hardware problems anyways......hope this helps...shia

In Safe Mode, your monitor will not be listed as it is using a generic device driver for basic display. Go into your video settings and reset it to the lowest resolution available. Reboot the computer into Vista again and your display should be working. If you check Device Manager now, you should see your monitor listed. If it isn't, you will need to load the Vista drivers for it. You can then modify your display settings to suit your preferences.

In this case you have to do the PC restore . you can do that in dell machines by shutting down the machine and when it is coming back on just HOLD DOWN THE CTRL ket and the START HITTING f11 key in this case you will lose the data which you have the on the c drive but this issue will get resolved .

Else you can try to restart in the safe mode with networking and then go to the system restore and then select the bold dates in which you have idea you system was working fine . selct the date and then do the system restore . In this case you will not lose the data but you will lose the updates which you have done after that date .

in both the cases system will work .

when the windows are going in the booting and it is colored black, the problem can be wrong with the windows or set the mode dual setting LCD 1st graphic assign it, try to use external LCD Monitor or connect to back of laptop

Press the start button then hold down F8 to go to a black screen with writing. Scroll to boot windows to last known good boot (maybe not exact words, but do last known good start) Click that option and windows should boot to the last good start of your computer.