Hi,I would recommend you perform startup repair. Follow these steps: To perform a Startup Repair follow the steps below: 1. Please insert the Windows 7 DVD and reboot the computer. 2. When we are prompted to press a key to boot from the DVD, please press Enter or the space bar. 3. Choose your language settings, and then click Next. 4. Click Repair your computer. 5. Select the operating system you want to repair, and then click Next. 6. On the System Recovery Options menu, click Startup Repair. Startup Repair might prompt you to make choices as it tries to fix the problem, and if necessary, it might restart your computer as it makes repairs. I also recommend you to update the graphic drivers and see if it makes any difference. You must be logged on as an administrator to perform these steps. 1. Open Device Manager by clicking the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager. If you are prompted for an administrator password or confirmation, type the password or provide confirmation. 2. In Device Manager, locate the device, and then double-click the device name. 3. Click the Driver tab, and then click Update Driver and follow the instructions.