>>>>Hi,
>>>>
>>>>I am considering upgrading my Windows 7 PC (which I use for all my development) to Windows 10.
>>>>I bought this Dell PC in 2013, replaced the hard drive to SSD drive some years later. So, as far as the hard disk, I know it has enough for the upgrade.
>>>>The PC has 16 GB of RAM.
>>>>Processor: Intel Core (TM) i7-3540M CPU @ 3.00 GHz.
>>>>
>>>>Two questions:
>>>>1. What do you check on this notebook to make sure it is compatible to Windows 10?
>>>>2. I I choose to reformat the drive and install Windows 10 from zero, does the pc/notebook have enough power to run it?
>>>>
>>>>TIA
>>>
>>>Windows will check that it can run on your machine during installation. My best suggestion is to replace the HD with a SSD, it's much faster and now they are cheap. That gives you the option to use the old HD for backup, or you can re-insert it.
>>>
>>>And yes, I'm sure that your machine is powerful enough.
>>
>>Thank you for your message. I already use/have the SSD drive on this computer.
>>Now I am deciding if I should reformat and install every program I have or upgrade.
>>I would love to hear from those who upgraded Windows 7 to Window 10 and see if they had any issues.
>
>I have done both, but a clean install is much better since you most likely have a lot of garbage on the old HD. As I wrote, I always buy a new SSD when I do a new installation on an old machine. That lets me use the old HD as for instance E: and check whatever you forgot to write down, or copy some files which stores important settings. Later you can buy a USB enclosure for the old HD, and use it an external drive.

Thank you for clarifying what you mean by the extra SSD drive.
My notebook/PC has 3 partitions: C: where all the programs are installed. No data on this partition. D: My data is on this partition; no applications. E: Some more data, no applications.
So, if I were to install Windows 10 as Window 10 Pro upgrade, it would all go to the C: drive.
And I know that I have some garbage on the C: partition, which would be cleaned. Mostly some old programs that I don't use.
But as far as the data, the upgrade should not effect it; since the upgrade should not "touch" D: and E: partitions.
I am just thinking of how to save time because installing all programs would take time. Vs, installing just what I really need.
Let me ask you (collective you) a question. If I were to install the Windows 10 Pro as new install, I would need to reformat the C: partition, correct?