Hello Devid,
I assume we're talking about Windows XP Pro when you say "factory settings?" And is your R40e updated to Service Pack 3? Recognizing
external DVD writers may not mean it has all the proper drivers for recognizing its own internal DVD drive... Anyway, this may or may not work for you. But I was just playing around with an R40 2723-3XU. I had set up XP Pro, SP3 with all the latest updates and drivers. It had no optical drive in the side. First, I removed any USB Flash drive, other USB devices, PCMCIA card, etc. so no pop up window or other auto-detecting would get in my way. I popped in a
DVD drive, that is, a DVD Rom only drive. It was
not auto-detected, and did
not show up in
MY Computer. DVD drive side light would come on, it would open/close, if I put in a CD or DVD it would spin for a moment, then stop. So I removed the DVD drive, popped it back in again, but it was still
not auto-detected. I knew this drive was good. I had previously tested it and labeled it as "noisy but good" LOL. So I went to My Computer, System properties, Hardware, Device Manager, chose "Scan for hardware changes" and of course, that didn't help.
So I took a
CDRW only drive, (note, it was not a CDRW/DVD Rom combo drive, but CDRW only), and popped it in. I heard that double-bell sound I had been waiting for and it was immediately
auto-detected. Windows popped up saying "installing device driver" and in a couple of seconds "your new hardware is ready to use." And of course it showed up in My Computer. So then I removed that CDRW only drive and popped in the
DVD Drive again and it was instantly
auto-detected, said "installing device driver", and "your new hardware is ready to use." And showed up in My Computer of course. I was then able to play a DVD movie.
So, to make a long story short- if you have one lying around, try a CD Rom or CDRW only drive first and see if that will trick Windows into installing the correct drivers. Remove it and then try the DVD Drive and see if it is auto-detected and shows up in MY computer. BTW, on these older computers it only shows "CD Drive" in my Computer even if it is a DVD Drive installed. Perhaps there is a way to change that.
So that little trick worked for me on an R40 but perhaps I had not snapped in the DVD Drive with enough force the first time I tried it. Maybe installing a CD Rom drive first has no benefit. Who knows?
But it's worth a try...
Have a great day,
Daniel.
No boot or anything. I just can not figure out the problem .... I restored factory settings again and again but did no help ... Guys please show me a way out..... 
... but the problem is i think i can repair the problem easily if i could open it up ... I opened the 2 keyboard locker screw but then i stuck up .... I can not remove the keyboard along with the mouse buttons ..... i think any video tutorial may help