Dell Inspiron 1520 with windows vista 2 days ago my computer crashed and when it powered up I received the prompt lsass.exe operation failure. It gives you two options... hit ok or hit the x box, both do the same thing which is reboot the computer. I've tried to run the windows disk to just re-install windows and it will not run the disk, the only disk I can get it to run is my drivers disk (Dell). I can only access the f2, f8 and f12 screen. please help

Hi, I would suggest try Startup repair and Using Last Known Good Configuration to check if you can log in the system. As you can boot into Safe Mode through F8, please launch your antivirus software and perform a system scan to make sure the system is clean. If it doesn't work, Inplace-upgrade is needed to resolve the issue. Note: After performing In-Place Upgrade, your personal data and installed programs usually will not be removed but we may need to run Windows Update to install all the available updates for your system to update these system files to the current version. This troubleshooting process is time consuming. Your patience is highly appreciated. As to the steps of In-Place Upgrade, I still would like to explain that it will reinstall all system files with this method. You may need to reinstall some applications to upgrade some files to a higher version, because they may be replaced during the installation of Windows. It will take about two hours to repair. Your personal files and settings will be kept as they were after the installation. However, it is always recommended to backup the important information and files to other partitions or other disks before doing it. If you would like to perform the In-place Upgrade, let’s refer to the following steps. 1. Start the computer by using the current Operating System. 2. Insert the Windows Vista DVD in the computer's DVD drive. 3. Use one of the following procedures, as appropriate: If Windows automatically detects the DVD, the Install now screen appears. Click Install now. If Windows does not automatically detect the DVD, follow these steps: a. Click Start, type Drive:\setup.exe, and then click OK. Note Drive is the drive letter of the computer's DVD drive. b. Click Install now. 4. When you reach the "Which type of installation do you want?" screen, click Upgrade to upgrade the current operating system to Windows Vista. Regards, Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.