No Video Display After Logon On Laptop LCD

This is on a fairly new HP G72 running Win7/64. A soft drink was spilled on the keyboard, system ran fine after cleaning it up, then performed a scan and found malware. Removed the malware, rebooted and system boots to user logon no problem. After you log in, the screen flashes white for several seconds, then goes black/white quickly and then all black: no cursor, no nothing. A few seconds later you hear the Windows startup song.Connect an external monitor and you see the desktop perfectly. System shows no problem with driver, all settings look good, system can see both an LCD screen and the external as disply devices. Use the Fn-F4 key to cycle througn video outputs and it goes blank-blank-external. Once you get past the logon screen in Normal mode the LCD goes blank but the external VGA works a treat!Boot into BIOS, let it run 15 minutes and never lose the display. Boot into the Recovery Console and let it set and poke around for 15 minutes and it never lose the display. Boot to Safe mode and poke around for 15 minutes and never lose the display. Boot to Normal mode and after you logon the screen goes black but with the external VGA working perfectly.

Uninstall the video drive (Intel HD), delete the driver on the system and boot into Normal mode: the LCD works perfectly, no problems other than 800x600 resolution and 256 colors. Install the latest & greatest video driver for the system from HP, reboot to Normal mode and the screen goes blank after logon but the VGA still works great. In frustration I do a destructive restore, taking the system back to new-out-of-the-box condition and still get the same problem.Only thing I haven't done yet is a HDD reformat and OS reinstall from recovery discs. Trying to avoid that so I don't lose the recovery partition. Don't know if this is a rootkit/bootkit problem but my next step is to try rebuilding the MBR and BCD. If that doesn't work all I can think of is reformat/reload.Doesn't all this look like a software problem? I want to think it's hardware (remember the soft drink spill) but if the LCD video works in BIOS, and works in Recovery Console, and works in Safe mode but *only* fails in Normal mode with both the OEM and latest drivers, doesn't that really point to the OS?