Windows boots up but the screen is completely blank

First, try booting into safe mode and un-installing all the Java Runtime Environments (JREs). Reboot after un-installing all the JREs. If prompted to reboot after one install, click no until all JREs have been un-installed.

Now, what do you mean by a blank screen? Do you see the Windows XP screen as it initially boots up, but then the screen just goes black? If this is the case, then your video settings probably got wedged. Perform the following steps to reset the video settings back to the default.

1) Boot the laptop into safe mode. Boot into safe mode with networking support if possible. This can be done by tapping the F8 key as the computer first turns on.

2) Once you are at the Desktop, right click on My Computer and select Manage.

3) In the window that appears, select Device Manager from the menu on the left.

4) Find Display Adapters on the right and click the plus sign. This will list the video adapter that you have.

NOTE: WRITE this down EXACTLY. You may need to go and get drivers for this. Seeing this is an older model, I doubt you'll need it, but better to be safe then sorry.

5) Go to your manufacturers support web site and download these drivers. You may not need them, but better to be safe then sorry.

http://tinyurl.com/lxn2p

NOTE: Skip step 5 if you did not boot with network support or cannot get to the Internet. This can be done from normal mode.

6) Right click on the display adpater and choose un-install. Hit OK on the window that appears and reboot the machine when the process is done.

7) The machine will take longer than usual to boot, as Windows XP is re-discovering the video adapter and resetting everything to the defaults. When it is done booting, the screen may look weird since the settings are now the defaults. You can the set them to what you want by right clicking on the desktop and selecting properties. Then go to the settings tab.

8) IF it did not re-discover the video adapter (this can be confirmed through the device manager), then go ahead and install the drivers. Windows Update will most likely also have the drivers.

this is a hardware problem...

great problem solved thanks

more google results pls