Medion Laptop M96980 horizontal lines after sleep mode

Graphics card is ATI Radeon X1200. No updates. I had Vista on this laptop, booted from Win 7 Pro 64 disk & installed on boot drive. Laptop boots fine, works fine. But if I allow it to drop into Sleep mode, and try to wake it, the monitor comes on covered with horizontal colored lines. Screen still visible behind lines, can log in, but lines remain. Checked with separate monitor, lines on that also. Any hope for this laptop? Is it the video card? Any suggestions? I looked for the driver, but AMD evidently doesn't support any more, and of course Medion had one cryptic vgae531xvst driver that I'm afraid to try because it doesn't look pertinent to the problem. Screen worked fine under Vista OS; but after Windows 7/64 Pro install, screen problem began. Another symptom is the speakers make a screeching sound whenever a key is pressed, at the same time the screen lines are present. I've shut down sleep mode in the hope that it will keep the laptop from developing the lines. The laptop works this way, but of course I'd prefer fixing whatever is causing this glitch on my monitor. Any and all suggestions appreciated.