Back on the old HP laptop

[creativeaccents]

Could be that the leads that provide power to the supply are loose. Could also be that surges have burned out one or more of your ram chips. Last, could be you need to reload some drivers.

[creativeaccents]

Remembered when I went downstairs; check those leads to the fans to assure that they are also tight. Some machines are designed to automatically shut down the power if the fans go out. If the power is hot and the power supply is working then the fans should come on and the boot process begins. Then, unless there is a RAM error or some code has been lost in the boot process, it searches for the drivers. But, from your description, it sounds as though you cannot even get far enough to do a "safe boot" with the F8.