Operating system is a Windows Vista Home premium (Vaio computer) which was installed when she won this computer... knows nothing about computers..

problem is not mine.. sister went to  uninstall program with her disk; now she has a black screen  with a white arrow.. i have tried to get her to restore the computer, power down,, unplug, remove battery and restart.. f8 safe mode.. nothing is working.. if ANYONE out there can help with do so.. she wants to throw her computer in the trash can.. thnks
 

Windows Vista Clean Install Process
http://esupport.sony.com/perl/support-info.pl?info_id=172

Unless your sister had created the Vista Recovery DVD, the only way to do a clean install would be to purchase a full copy (or if a friend or you have a full blown OEM Vista with the same flavor as the one on the VAIO, e.g. Vista Premium, Enterprise, etc.) of VISTA or better upgrade to Windows 7...

and if a copy (or the recovery DVD) of Vista is not available, then I am afraid you will need to contact a professional, who has the means and the knowledge to do the clean install...
 

Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

As above, a clean install is probably required, but I would suggest that you create a bootable CD or USB drive with Linux (Ubuntu) & recover any personal data first. Windows 7 would work better than Vista.

have you walked her through trying to run starup repair for Vista?  It doesn't seem to work as well as windows 7, but it does work sometimes.

1. When the computer boots, just before Windows would load, start tapping the <F8> key.
2. On the next black screen with white text, look for anything that says "startup repair" or the like - I forget the exact verbiage.
3. Click OK or whatever, go through that, it may take a while, so once started, may want to do something else and come back.

If that doesn't work, try <F8> and then safe mode.  If she can get into safe mode, then it could be as simple as finding a startup item or a service that is having issues and kill it.  Well, actually, if gets to that point, may can use System Restore
- if can't then may need to do the following to turn off/disable some startup items and services:
1. <Windows Key> + <R>, type msconfig and press <Enter>
2. Change the startup type on the first tab to "diagnostic startup"
3. Reboot, and see if Windows boots now, but just with most everything not enabled/turned on.
4. If it does, go back to msconfig and go to the startup tab.  Start re-checking items one at a time.  Well, she could try more than one, but more likely to get the issue sooner that way, and then have to verify between items.  So basically, check one item, reboot, see what happens.  If good, go on to the next one until get the black screen.  Once verify the problematic startup item or service, always leave that one disabled, and go about your business.

Another thing that could help: Install (if can get to Safe Mode with Networking, at least) CCleaner, run the Cleaner and the Registry Scrub, fix all found items.. run until all items gone (registry) or else only one or two remaining.  Could be that the program uninstaller didn't fully complete, so doing this may clear out whatever was left in registry settings.

Of course a full re-install is always best, but there are other options, possibly.

When you say she uninstalled with her disk, what program was she uninstalling?  Knowing that could help be more specific with fixes, and you might even find a walk through online for the specific issue.