I put all the stuff togheter again but it didn´t showed video, it doesn´t make any sound; the hard disc drive indicator flashes twice, so the cdrom light and the lan indicator. I tried to plug the vga output to an external monitor but nothing happened, still no video, I tried to reset bios, I took out the battery of bios and leave it unplugged around 16 hours (I took the main battery also) but nothing happens still the same result

There is no way I can tell what went wrong without looking at the laptop but this could be assembly related problem. Maybe you didn’t plug some cables correctly.
Did you check memory modules? Have you tried reseating them?

Yes, about step 9. You didn’t specifically say how to remove the power button ribbon. I don’t want to fiddle with it too much and break it. How do you do it?

This connector doesn’t have any locking tab. In order to disconnect the cable you just carefully pull it from the connector. When assembling it back together, push the cable into the connector.

BTW, any processor upgrades you feel are worthwhile on this machine?

Again,
Thanks!

I tried upgrading my F730US’ memory to 4Gb using 2 DDR2 PC-6400 memory modules from PNY and it would not boot. Kept repeating a pattern when I turned it on: accessing the DVD and hard disk and then the power light would flash twice. Put old 1GB modules back and no issues. I have the latest BIOS on as well.

Any ideas? Should I have used PC-5300 instead?

PC-6400 suppose be backward compatible with PC-5300.
But I’ve seen some laptops working properly with PC-5300 modules but failing to boot with PC-6400. Not sure if your laptop is one of those.
Make sure memory module properly connected to slots.
According to HP, F730US should be able to run with 4GB.
What happens if you install only one 2GB RAM module? Will it boot?

Any ideas? Should I have used PC-5300 instead?

Thanks!

i have a problem with my Presario F500. 1st issue is Wifi card light is always orange and no drivers shown in device Manager but some times may be in a month or later it goes to blue but for a little time…. what can i do for this problem…. 2nd problem is that often when i play any video after some time it goes Hang…. this is major Issue… plz help me for this and tell me can i replace my vga card or not.

It’s likely that both issues (wireless failure and video failure) are related to the graphics card failure. It’s a known issue with some HP/Compaq laptops.
You cannot replace the VGA card because the video chip is integrated into the motherboard. If the video chip fails, the entire motherboard has to be replaced.
You can try this trick: http://www.laptoprepair101.com/laptop/2011/02/23/fix-laptop-motherboard-with-failed-nvidia-graphics-chip/
But do it only if you have nothing to lose. Proceed at your own risk.