Hello ,
I've been dealing with windows 10 for awhile on several of my PC's for a year or so, and I am familiar with Desktop's and Laptop's alike, and all I can say is in the begging of the Windows 10 Developer's Preview ISO files' if you are Dual Booting Like I did with Dell Laptop's 1525 Inspiron or 1737 Studio in which I am working Win 10 Pro after my final upgrade 3 day's ago, right now contacting you about this problem is.
For some reason Dell PC Laptop's won't accept Win 10 correctly in dual boot mode's, but if you do a fresh install without the dual boot of other Windows OS on the same PC like like I did with Dell Laptop's in the beginning ,Like I did on this 1737 Studio Dell which was made in 2009 it work's with no real bugs or issue's. For some reason the OS work's great on a Dell if you make sure you go to the Dell site on line and upgrade all of your driver's from the Dell site according to your specific Laptop Model and make,after the install of Windows 10.
And some of the Developer Series Build's have a problem with the Start button responding, or showing up just restart and press F9 and it will take you to the troubleshoot tile and recovery tile on a blue screen, and you have the option to recover the PC to the beginning of the redoing the files of the OS your installing. I had the same problem twice on my 1525 Insprion Laptop's which I have 2 so, I had to not use the Win 10 in those particular Laptop's because I am using Win 7 Ultimate and Vista Ultimate Dual Boot on my PC and my wife got so disgusted with the test's in the past with the previous build's on her's she wanted her Win 7, back because I had Win 7 and Win 10 on the same PC and it was interfering with her Win 7 so she just has Win 7 on her 1525 Insprion.
But now since the final upgrade is out, I had a upgrade 3 days ago on my 1737 Studio, and it affected the files on the old build that was already in place on the old build, and I restored like I suggested to you in this forum, and it work's perfectly, but I did have to check and make sure my drivers were on line, after the redo of the OS, and I had to reinstall some of the app's from the Microsoft store but it is great now. I would prefer Dell Laptop's myself because of the durability and reliability, but I have a HP Pavilion Entertainment PC that was made in 2007, and it has been smooth with the Dual Boot Mode Set Up, it has Win 7 Ultimate, and Vista Ultimate, and Win 10 all on the same Laptop, and it work's perfectly.Due to my personal trial's and error's."
So, I think a lot of the problem's with a Dell is their configuration of their driver's, according to the Make and Model you can only get specific driver's, and it has conflict with the Win 10 OS to some degree. I also read that Dell is or was trying to make a software deal to Microsoft to get them to pay for certain permissions to download their OS on their PC's, and Server's, back 7 or 8 month's ago, but I believe due to their bully tactic's in, (which you can't believe all that you read, you have to use your own judgement, according to your personal experience) HP got fist contract's signed to download and use the new OS in their PC's, and server's first before Dell pulled their head out of their a** so, dude I hope this help's, and you can come up with a solution wit your problem.
The Developer's Build's in the past were test's for them to build a complete secure OS to take back some of the market share due to Steve Ballmer's mismanagement of Win 8,and get back on track like when 75 to 80% of the Market Share was Windows XP PC's back in 2002. Apple has the majority market share now, and has since a little been after Win 7 had so many bugs in it in the beginning. I know because I had to use 3rd party driver finder's to straighten out a lot of my issues with Dells specific and select driver site in order to get my dell PC's to act right with Win 10.